It is narrated from Hazrat Abu Saeed (may Allah be pleased with him) that a person asked the Prophet (peace and blessings be upon him) about coitus interruptus (withdrawal). The Prophet (peace and blessings be upon him) said: Do as you wish, whatever Allah has decreed will happen, and not every drop of semen results in a child. And when Allah intends to create someone, no one can prevent it.