idiots.
im not using clinical terms, but...when a pregnant chick is getting fucked, due to the anatomical design of the pelvis, as well as the angle of entry, the dick hits the 'back' of the pussy. the baby is 'above' the pussy. meaning...no dick is big enough to knock on the kids head.
i do know of a negress that went into labor after trying to breed. theres no way to know if the act of breeding caused the labor or if it was just the babys time to want to gtfo
to the OP:
you fucking idiot...if you cant control how deep your dick goes into any orifice you need to not have sex.
get a pair of scissors and cut your wang in half. problem solved