Yolk or bicyclist babies are babies commonly known as twins, these babies are conceived independently, which is to say that they are two or more eggs fertilized by different spermatozoa, of course these pregnancies are the subject of great questions, Because although there are some genetic relationships, or assisted manipulation, other vitelline pregnancies appear without responding to any of these cases.
Among the antecedents that can be taken into account as probability of having a yolk pregnancy, we can mention:
Maternal obesity, many specialists talk about a close relationship between overweight and multiple pregnancies.
The mother of more than 30 years, this is justified, because the woman after the 35 years, begins to have hormonal alterations, something that increases the possibility that the woman in its period of ovulation releases more of a ovule, for a Hormonal over-stimulation, therefore some specialists assure, greater maternal age, greater possibility of having a multiple pregnancy.
Inherited factors, if in the family of the new parents, have had multiple pregnancies, the couple is more likely to have yolk babies, regardless of whether the inheritance comes from the maternal or paternal side.
Having previous multiple pregnancies, couples who have already had multiple pregnancies are twice as likely to return to multiple pregnancies as one could say that a woman has a tendency to have multiple ovulation.
Undergoing assisted reproduction techniques, the fact of undergoing these techniques considerably increases the occurrence of multiple pregnancies.
It is possible to mark the difference these babies of the twins, since the twins are two babies or more that each one was fertilized of independent way and therefore each one will have its own bag, reason why these babies can be of different sex and in addition Although they are similar to each other, are not identical.