The moment when the new life arises

After овуляции яйцеклетка lives during 6 — 12 ч. At this particular time there can be its fertilisation. If after 12 ч яйцеклетка not оплодотворе­на, it perishes.
Man's сперматозоиды reach a place of possible fertilisation approximately in an hour. They make a considerable way: from a vagina through a uterus neck in a cavity of a uterus and then in яйцеводы. Сперматозоиды live longer, than female яйцеклетки: from two about three days. The conclusion from here follows, that the period воз­можного fertilisations lasts some days.

Fertilisation

Ripened яйцеклетка is on the brink яйцевода (маточной pipes). This place should reach сперматозоид to take root into it, i.e. here there is a fertilisation. Usually in яйцеклетку one gets сперматозоид, however there are cases when in яйцеклетку two get сперматозоида or бо­лее, but it is not reflected in normal process of fertilisation.
Twins are born rather seldom. Однояйцовые twins always one-its floor. Twins of a different floor are formed always of two яйцеклеток which are impregnated by two сперматозоидами.