Twins, a captivating phenomenon, come in two forms: identical and fraternal. Identical twins arise from a single fertilized egg splitting into two embryos, resulting in genetically identical individuals. Fraternal twins, on the other hand, result from the fertilization of two separate eggs by two different sperm, making them as similar as any other siblings.
Twin rates are on the rise, primarily due to fertility treatments and women delaying motherhood. They also vary across racial groups, with African-American women having higher rates than other groups.
While identical twinning appears random, fraternal twinning has a familial connection, with a higher chance of occurrence if a mother’s family history includes fraternal twins. This is attributed to a gene predisposing some women to hyperovulation, releasing multiple eggs per cycle.
Despite sharing DNA, identical twins are not perfect copies. Their fingerprints, initially identical, become distinct due to environmental іпfɩᴜeпсeѕ in the womb. Similarly, their freckle patterns differ due to random mᴜtаtіoпѕ.