Fraternal twins can be of the same or different sexes. Identical twins are also called monozygotic twins. They result from the fertilization of a single egg with a single sperm. And as those cells divide and multiply, at some point very early in embryonic growth they split into two individuals.
So that you can imagine that the genetic material in these two identical twins is identical to each other, hence the name. Our Sponsors Log in Register. Log in Register. Ages and Stages. Healthy Living. Safety and Prevention. Family Life. Health Issues. Tips and Tools. Our Mission. Find a Pediatrician. Text Size. Page Content.
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. These babies will be no more alike than siblings born at separate times. The babies can be either the same sex or different sexes, with the odds roughly equal for each. It is proposed that the egg splits in two, and each half is then fertilised by a different sperm. This theory is an attempt to explain why some fraternal twins look identical. Gestation for twins The normal length of gestation for a single baby is around 40 weeks.
However, gestation for twins, either identical or fraternal, is usually around 38 weeks. Since twins are usually premature, they are more likely to have lower birth weights. Prematurity is associated with increased risk of a number of disorders, including jaundice.
Giving birth to twins Childbirth can give rise to complications when just one baby is present, so twins present extra potential for difficulties. It is advised that women carrying twins give birth in hospital, rather than at home. The babies can be delivered vaginally, but caesarean section delivery may be considered a better alternative in some circumstances.
Zygosity testing It is difficult to tell if twins are identical or fraternal at birth. Some identical twins may be born with individual sets of membranes, which may lead to the mistaken assumption that the babies are fraternal. One way to tell the difference is to have the twins DNA-tested. Identical twins share the same genetic information, while fraternal twins share around half.
The test can be done with a sample of cheek cells, collected painlessly. Other tests include blood group examinations. Where to get help Your doctor Paediatrician Maternity hospital Things to remember Twins account for over 90 per cent of multiple births. To form identical or monozygotic twins, one fertilised egg ovum splits and develops into two babies with exactly the same genetic information.
To form fraternal or dizygotic twins, two eggs ova are fertilised by two sperm and produce two genetically unique children. Your likelihood of conceiving twins or more , BabyCentre, Inc. More information here.
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