The occurrence of twins

The process of biological twins is when the fertilization of eggs by sperm membantuk buahi zygote, then this zygote will divide. If cleavage occurs when the zygote at the beginning of fertilization (1-3 days after fertilization), the embryo will usually have different amniotic bag, and one placenta.

But when the division for 14 days then it is likely there will be twins join / stick together on the part of the body or imperfect division called Siamese twins
So Conjoined twins occur in monozygot. With ultrasound examination (utrasonografi) doctor can assess the state of the fetus, gender, disability or defect positions etc..

Twin Dizygotik
Fraternal twins are also called twin dizygotik, the twins come from two eggs. They usually do not look much like their brethren bleak

Do not always have the same gender, with 50% of fraternal twins are boys - girls, 25% were boys - and men and 25% more are girls - children perempuan.Proses fraternal twinning , which is due at the time of conception there are two mature eggs each in buahi by a different sperm.

Fraternal twins come from two different eggs and sperm, each of which has its own amniotic sac and placenta own. So fraternal twins, is 2 fertilization process in a single pregnancy.

Approximately 2/3 part of the twins are fraternal twins. Usually the doctor will be able to express identical or fraternal twins after the birth of the placenta level has.