Why is it possible to conceive twins with different fathers?

A woman must release two eggs simultaneously during the same menstrual cycle, and both eggs must be fertilized by two different sperm; this situation is extremely rare.

Recently, a father in Hoa Binh took his twin children for a DNA test, and the results were surprising, showing that only one of the babies was his.Deputy Minister of Health Nguyen Viet Tien stated that this is a rare case.It's necessary to re-examine whether the woman is carrying a monozygotic or fraternal pregnancy, and a genetic test is needed to get an accurate answer.

According to Deputy Minister Tien, sTwins, or multiple births, are a common phenomenon where a mother gives birth to two babies in a single pregnancy. Twin babies can be identical in sex and appearance, but they can also be completely different in both sex and appearance. This depends entirely on whether the mother's pregnancy resulted in identical or fraternal twins.

Photo: Health.

In medical terms, identical twins occur when a single egg is fertilized by a single sperm and splits into two during the zygote development stage, resulting in two separate fetuses. These fetuses are virtually identical in both appearance and genetic structure. They also usually share the same sex.

Fraternal twins occur when a woman releases two eggs simultaneously during the same menstrual cycle, and both eggs are fertilized by two different sperm. In this case, the two fetuses share the mother's uterus for nine months but develop in completely different directions.different.In the case of fraternal twins, it is very likely that the father of the two babies is not the same person.

SleepThere have been a few cases of twins with different fathers around the world. Experts can only explain this rare phenomenon by saying that when a mother releases multiple eggs in the same menstrual cycle and has intercourse with more than one partner, each egg can be fertilized by a different man, leading to significant differences between the twins. Even the two twins may not be born at the same time.

In some cases, a mother who has already become pregnant conceives again when one egg is fertilized by a different sperm in the same month. This phenomenon is called superfetation. It occurs a few weeks after the first zygote has formed. It also explains why, at birth, one twin is larger and more mature than the other.

Biologically, a woman can conceive fraternal twins with two different men after she has become pregnant and ovulated again. One fetus forms when the second egg is fertilized by sperm from a different man.

This is also true for triplets, which include a pair of identical twins and a baby who looks different from the other two. You can tell if twins are identical by their identical appearance, while fraternal twins look like their other siblings. This is why placental membranes are examined so carefully. Placental or DNA testing will determine whether they are identical or fraternal twins. However, not all results are completely accurate.

According to Deputy Minister Tien, twin pregnancies are more common among those undergoing in-vitro fertilization (IVF). The success rate of IVF is only about 35-40%, so to increase the chances of success, doctors will transfer more than one embryo into the woman's uterus during IVF, thus resulting in cases of twins or triplets.

Sometimes, due to anxiety about IVF failure, many couples request that doctors fertilize an additional egg with sperm from a sperm bank to create an embryo. These two embryos are then transferred into the mother's uterus to develop into fetuses. Fortunately, both embryos develop well, and the mother gives birth to two healthy babies. In this case, the twins will have one baby carrying DNA from the father's sperm and the other carrying DNA from the donor's sperm.

According to VNE