{"id":26981,"date":"2025-03-14T08:00:37","date_gmt":"2025-03-14T08:00:37","guid":{"rendered":"https:\/\/www.may.app\/?p=26981"},"modified":"2025-09-30T08:57:17","modified_gmt":"2025-09-30T08:57:17","slug":"girl-and-boy-twins-mixed-twins","status":"publish","type":"post","link":"https:\/\/www.may.app\/en\/blog\/pregnancy\/girl-and-boy-twins-mixed-twins\/","title":{"rendered":"Girl-and-boy twins: everything you need to know about mixed twins"},"content":{"rendered":"\r\n<p><span style=\"font-weight: 400;\">You were recently diagnosed with a twin pregnancy and you\u2019ve just learned the sex of your babies? This article explains <strong>mixed-sex twins<\/strong>, meaning a girl-and-boy twin pair. What are the different types of twins? What changes for pregnancy monitoring?<\/span> <span style=\"font-weight: 400;\"><strong>Girl-and-boy twins<\/strong>: understand it all.<\/span><\/p>\r\n<h2><span style=\"font-weight: 400;\">Girl-and-boy twins: what are we talking about?<\/span><\/h2>\r\n<p><span style=\"font-weight: 400;\"><strong>Mixed-sex twins<\/strong>, commonly called \u201cfraternal twins,\u201d are so-called \u201c<strong>dizygotic<\/strong>\u201d twins who are <strong>of different sexes<\/strong>. They are generally contrasted with monozygotic (\u201cidentical\u201d) twins.<\/span><\/p>\r\n<ul>\r\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Monozygotic twins<\/strong>: from a single fertilized egg, they <strong>share 100% of their genetic makeup<\/strong> and are always the same sex. They may share the same placenta and even the same sac, although this is <strong>not the most common<\/strong>.<\/span><\/li>\r\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Dizygotic twins<\/strong>: from two different eggs fertilized by different sperm, they <strong>do not have the same genetic makeup<\/strong> and each has their own sac and their own placenta.<\/span><\/li>\r\n<\/ul>\r\n<p><span style=\"font-weight: 400;\"><strong>Mixed-sex twins<\/strong> \u2014 girl and boy \u2014 show a <strong>genetic diversity similar to siblings born from different (non-twin) pregnancies<\/strong>. For example, one twin may have blue eyes while the other has brown, differences in height and build, or even skin tone.<\/span> <span style=\"font-weight: 400;\">Good to know: there is also <strong>a third type of twins<\/strong>, conjoined twins. This is a <strong>rare form of identical twins<\/strong>, in which the embryos do not fully separate, so they are <strong>connected by a part of the body at birth<\/strong>. Such births are <strong>extremely rare<\/strong>.<\/span> <img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-20470\" src=\"https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/baby-boy-twins-2025-01-08-02-59-06-utc.webp\" alt=\"Girl-and-boy twins: all about mixed-sex twins may app health\" width=\"1581\" height=\"1183\" title=\"\" srcset=\"https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/baby-boy-twins-2025-01-08-02-59-06-utc.webp 1581w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/baby-boy-twins-2025-01-08-02-59-06-utc-300x224.webp 300w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/baby-boy-twins-2025-01-08-02-59-06-utc-1024x766.webp 1024w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/baby-boy-twins-2025-01-08-02-59-06-utc-768x575.webp 768w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/baby-boy-twins-2025-01-08-02-59-06-utc-1536x1149.webp 1536w\" sizes=\"auto, (max-width: 1581px) 100vw, 1581px\" \/><\/p>\r\n<h2><span style=\"font-weight: 400;\">Having mixed-sex twins: what\u2019s the probability?<\/span><\/h2>\r\n<p><span style=\"font-weight: 400;\"><strong>Each fetus has a 1-in-2 chance of being a boy and a 1-in-2 chance of being a girl<\/strong>. Thus, if you have a dizygotic pregnancy, you have a 1-in-4 chance of having 2 girls, a 1-in-4 chance of having 2 boys, and <strong>a 1-in-2 chance of having mixed-sex twins<\/strong>!<\/span> <span style=\"font-weight: 400;\">Having mixed-sex twins, i.e., a girl and a boy, is <strong>relatively rare\u2014just like having twins at all<\/strong>. Nevertheless, this is a <strong>figure that tends to increase<\/strong> as twin births rise. According to the <\/span><span style=\"font-weight: 400;\">National Institute for Demographic Studies<\/span><span style=\"font-weight: 400;\"> (INED), twin births represented <strong>9 deliveries per 1,000<\/strong>, i.e., <strong>0.9% of births worldwide in the 1980s<\/strong>. This figure rose to <strong>1.2% in the 2010s<\/strong>. In France, twins represent <strong>1.5% of births today<\/strong>. Several factors explain these numbers.<\/span><\/p>\r\n<h3><span style=\"font-weight: 400;\">Genetic factors<\/span><\/h3>\r\n<p><span style=\"font-weight: 400;\"><strong>Genetic background plays a significant role<\/strong> in the likelihood of having dizygotic twins. Specifically, if there is a <strong>family history of twin births<\/strong> (particularly on the maternal side), you are more likely\u2014or less, depending on your point of view\u2014to be expecting twins. This is called a <strong>genetic predisposition to multiple ovulation<\/strong>, where more than one egg is released in a menstrual cycle.<\/span><\/p>\r\n<h3><span style=\"font-weight: 400;\">Other factors<\/span><\/h3>\r\n<p><span style=\"font-weight: 400;\"><strong>Several other factors<\/strong> can influence the probability of having twins:<\/span><\/p>\r\n<ul>\r\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Your age<\/strong>: women aged 35 and over (sometimes historically labeled \u201cgeriatric pregnancies,\u201d though that term is no longer used\u2014people now say later-in-life pregnancies, which are increasingly common) have a higher likelihood of twin pregnancy.<\/span><\/li>\r\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Fertility treatments<\/strong>: treatments such as ovarian stimulation can encourage the release of multiple eggs, increasing the chances of conceiving dizygotic twins.<\/span><\/li>\r\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Number of previous pregnancies<\/strong>: women who have already had one or more pregnancies have a slightly higher probability of having twins.<\/span><\/li>\r\n<\/ul>\r\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-20473\" src=\"https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/children-s-day-sweet-funny-baby-on-bed-in-childre-2025-01-09-03-08-18-utc.webp\" alt=\"Girl-and-boy twins: all about mixed-sex twins may app health\" width=\"2018\" height=\"1345\" title=\"\" srcset=\"https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/children-s-day-sweet-funny-baby-on-bed-in-childre-2025-01-09-03-08-18-utc.webp 2018w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/children-s-day-sweet-funny-baby-on-bed-in-childre-2025-01-09-03-08-18-utc-300x200.webp 300w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/children-s-day-sweet-funny-baby-on-bed-in-childre-2025-01-09-03-08-18-utc-1024x682.webp 1024w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/children-s-day-sweet-funny-baby-on-bed-in-childre-2025-01-09-03-08-18-utc-768x512.webp 768w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/children-s-day-sweet-funny-baby-on-bed-in-childre-2025-01-09-03-08-18-utc-1536x1024.webp 1536w\" sizes=\"auto, (max-width: 2018px) 100vw, 2018px\" \/><\/p>\r\n<h2><span style=\"font-weight: 400;\">The different types of twin pregnancy<\/span><\/h2>\r\n<p><span style=\"font-weight: 400;\">Just as there are <strong>different types of twins<\/strong>, there are <strong>different types of twin pregnancies<\/strong>, whose monitoring and implications for birth may vary. Your follow-up is <strong>generally adapted based on the placenta(s) and the amniotic sac(s)<\/strong>\u2014though these are not the only criteria\u2014in order to anticipate potential complications. Here are the possible scenarios:<\/span><\/p>\r\n<ul>\r\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Dichorionic diamniotic pregnancy<\/strong>: each embryo has its own placenta and its own amniotic sac. This is the lowest-risk type of twin pregnancy.<\/span><\/li>\r\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Monochorionic diamniotic pregnancy<\/strong>: the embryos share the same placenta but each has their own amniotic sac.<\/span><\/li>\r\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Monochorionic monoamniotic pregnancy<\/strong>: the embryos share the same placenta and the same amniotic sac, which increases the risk of complications.<\/span><\/li>\r\n<\/ul>\r\n<p><span style=\"font-weight: 400;\">These distinctions\u2014along with your health status, history, age, and the babies\u2019 development\u2014influence <span style=\"font-weight: 400;\">your pregnancy monitoring<\/span> as well as your care on the day of birth. Monochorionic pregnancies generally require <strong>more intensive monitoring<\/strong> than dichorionic ones.<\/span> <img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-8734\" src=\"https:\/\/www.may.app\/wp-content\/uploads\/2024\/11\/happy-pregnant-woman-expecting-twins-pregnant-wo-2023-11-27-05-33-40-utc.webp\" alt=\"Fraternal twins: understand it all may app health\" width=\"1000\" height=\"563\" title=\"\" srcset=\"https:\/\/www.may.app\/wp-content\/uploads\/2024\/11\/happy-pregnant-woman-expecting-twins-pregnant-wo-2023-11-27-05-33-40-utc.webp 1000w, https:\/\/www.may.app\/wp-content\/uploads\/2024\/11\/happy-pregnant-woman-expecting-twins-pregnant-wo-2023-11-27-05-33-40-utc-300x169.webp 300w, https:\/\/www.may.app\/wp-content\/uploads\/2024\/11\/happy-pregnant-woman-expecting-twins-pregnant-wo-2023-11-27-05-33-40-utc-768x432.webp 768w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/><\/p>\r\n<h2><span style=\"font-weight: 400;\">Medical monitoring of a twin pregnancy<\/span><\/h2>\r\n<p><span style=\"font-weight: 400;\"><strong>Medical follow-up for a twin pregnancy<\/strong> is <strong>a bit different<\/strong> from that of a singleton pregnancy (one baby), since twin pregnancies carry a <strong>higher risk of complications<\/strong>.<\/span><\/p>\r\n<h3><span style=\"font-weight: 400;\">Frequency of appointments<\/span><\/h3>\r\n<p><span style=\"font-weight: 400;\">One of the main differences in follow-up concerns <strong>the frequency of appointments and ultrasounds<\/strong>.<\/span><\/p>\r\n<ul>\r\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Ultrasounds<\/strong>: from the first trimester, monthly ultrasounds are recommended to monitor the twins\u2019 development. This frequency may increase to twice monthly, or even weekly, if there are potential complications such as intrauterine growth restriction (IUGR) or threatened preterm labor.<\/span><\/li>\r\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Medical appointments<\/strong>: at least monthly follow-up is recommended, generally within the maternity unit where the birth will take place.<\/span><\/li>\r\n<\/ul>\r\n<h3><span style=\"font-weight: 400;\">Personalized care<\/span><\/h3>\r\n<p><span style=\"font-weight: 400;\"><strong>Not all twin pregnancies require the same intensity of monitoring<\/strong>; therefore\u2014as with any pregnancy\u2014you will receive <strong>personalized care<\/strong> tailored to your needs to ensure your safety and that of your babies.<\/span> <span style=\"font-weight: 400;\">As mentioned above, <strong>monochorionic pregnancies require special attention<\/strong> due to the <strong>increased risk of complications<\/strong>. These are often followed in <strong>level II or III maternity units<\/strong>, which have the resources needed to manage <span style=\"font-weight: 400;\">preterm births<\/span> and handle potential complications.<\/span> <span style=\"font-weight: 400;\">Good to know: in cases of high risk of preterm birth, home visits by a midwife can be arranged to perform fetal monitoring and check the condition of the cervix.<\/span> <span style=\"font-weight: 400;\">Want to learn more? Feel free to <\/span><a href=\"https:\/\/app.adjust.com\/1pblulz8\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">download the May app<\/span><\/a><span style=\"font-weight: 400;\">, where you&#8217;ll find plenty of resources to support and guide you throughout your pregnancy.<\/span> <img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-20479\" src=\"https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/twin-boys-being-silly-2025-01-09-10-17-54-utc.webp\" alt=\"Girl-and-boy twins: all about mixed-sex twins may app health\" width=\"1195\" height=\"797\" title=\"\" srcset=\"https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/twin-boys-being-silly-2025-01-09-10-17-54-utc.webp 1195w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/twin-boys-being-silly-2025-01-09-10-17-54-utc-300x200.webp 300w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/twin-boys-being-silly-2025-01-09-10-17-54-utc-1024x683.webp 1024w, https:\/\/www.may.app\/wp-content\/uploads\/2025\/03\/twin-boys-being-silly-2025-01-09-10-17-54-utc-768x512.webp 768w\" sizes=\"auto, (max-width: 1195px) 100vw, 1195px\" \/><\/p>\r\n<h2><span style=\"font-weight: 400;\">Expecting twins: what changes at birth?<\/span><\/h2>\r\n<p><span style=\"font-weight: 400;\">When you\u2019re expecting twins\u2014whether they\u2019re different sexes (a girl and a boy) or the same sex\u2014<strong>the birth may require a few extra precautions<\/strong>.<\/span><\/p>\r\n<h3><span style=\"font-weight: 400;\">Vaginal birth or cesarean?<\/span><\/h3>\r\n<p><span style=\"font-weight: 400;\"><strong>Vaginal birth is generally possible with twins<\/strong>, especially if the first baby is head-down. However, some situations require <span style=\"font-weight: 400;\">a cesarean<\/span>, notably in monochorionic monoamniotic pregnancies (where identical twins share the same placenta and the same amniotic sac) or in cases of complications such as <span style=\"font-weight: 400;\">growth restriction<\/span> or a significant weight difference between the babies.<\/span><\/p>\r\n<h3><span style=\"font-weight: 400;\">A larger medical team present<\/span><\/h3>\r\n<p><span style=\"font-weight: 400;\">A twin birth involves <strong>a larger medical team<\/strong> due to the risk of complications. You can expect the presence of an obstetrician-gynecologist, midwives, nursery assistants, and sometimes a nurse. <span style=\"font-weight: 400;\">Anesthetists<\/span> and pediatricians may also be present, ready to intervene quickly if needed. <strong>This ensures each baby receives the necessary attention and care from birth.<\/strong><\/span><\/p>\r\n<h3><span style=\"font-weight: 400;\">Epidural: a recommended option<\/span><\/h3>\r\n<p><span style=\"font-weight: 400;\">Of course, <span style=\"font-weight: 400;\">the choice to have an epidural<\/span> is yours. However, <strong>for twin births, note that it will often be recommended<\/strong> a bit more strongly than usual because it can be very helpful in case of complications (the need for an internal version of the second baby, emergency cesarean\u2026). If the idea of an epidural worries you, <strong>don\u2019t hesitate to discuss it with your medical team to tailor the procedure to your preferences<\/strong>.<\/span><\/p>\r\n<h3><span style=\"font-weight: 400;\">Increased monitoring during labor<\/span><\/h3>\r\n<p><span style=\"font-weight: 400;\">Although it is sometimes possible to disconnect monitoring during straightforward singleton labors without complications, <strong>this is not the case for twin births<\/strong>. Monitoring helps <strong>track the babies\u2019 heart rates<\/strong> to respond quickly if needed.<\/span> <span style=\"font-weight: 400;\">There are therefore <strong>different types of twins<\/strong>, including <strong>mixed-sex twins with a boy and a girl<\/strong>. In all cases, a twin pregnancy requires <strong>more attentive monitoring<\/strong> as well as <strong>greater supervision on the day of birth<\/strong>. Don\u2019t hesitate to discuss these topics with your healthcare professionals to prepare as well as possible for this double motherhood.<img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-8736\" src=\"https:\/\/www.may.app\/wp-content\/uploads\/2024\/11\/portrait-of-sleeping-newborn-baby-girl-lying-besid-2024-09-15-20-36-35-utc.webp\" alt=\"Fraternal twins: understand it all may app health\" width=\"1000\" height=\"667\" title=\"\" srcset=\"https:\/\/www.may.app\/wp-content\/uploads\/2024\/11\/portrait-of-sleeping-newborn-baby-girl-lying-besid-2024-09-15-20-36-35-utc.webp 1000w, https:\/\/www.may.app\/wp-content\/uploads\/2024\/11\/portrait-of-sleeping-newborn-baby-girl-lying-besid-2024-09-15-20-36-35-utc-300x200.webp 300w, https:\/\/www.may.app\/wp-content\/uploads\/2024\/11\/portrait-of-sleeping-newborn-baby-girl-lying-besid-2024-09-15-20-36-35-utc-768x512.webp 768w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/><\/span> ** Photo credits: hwilson8 | StudioLucky | Alex_Studio_Ukraine | champzy<\/p>\r\n<p><span style=\"font-weight: 400;\">This text was translated from French by an artificial intelligence. The information, advice, and sources it contains comply with French standards and may therefore not apply to your situation. Make sure to complement this reading by visiting the May US\/UK app and consulting the healthcare professionals who are supporting you.<\/span><\/p>","protected":false},"excerpt":{"rendered":"<p>You were recently diagnosed with a twin pregnancy and you\u2019ve just learned the sex of your babies? This article explains mixed-sex twins, meaning a girl-and-boy twin pair. What are the different types of twins? What changes for pregnancy monitoring? Girl-and-boy twins: understand it all. Girl-and-boy twins: what are we talking about? Mixed-sex twins, commonly called [&hellip;]<\/p>\n","protected":false},"author":23,"featured_media":20483,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[186],"tags":[154],"class_list":["post-26981","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-pregnancy","tag-fetal-development"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/posts\/26981","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/users\/23"}],"replies":[{"embeddable":true,"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/comments?post=26981"}],"version-history":[{"count":3,"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/posts\/26981\/revisions"}],"predecessor-version":[{"id":26984,"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/posts\/26981\/revisions\/26984"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/media\/20483"}],"wp:attachment":[{"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/media?parent=26981"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/categories?post=26981"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.may.app\/en\/wp-json\/wp\/v2\/tags?post=26981"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}