Beginning of Creation

Bukhari :: Book 4 :: Volume 54 :: Hadith 503

Narrated Ibn 'Abbas:

The Prophet said, "If anyone of you, on having sexual relation with his wife, says: 'O Allah! Protect me from Satan, and prevent Satan from approaching the offspring you are going to give me,' and if it happens that the lady conceives a child, Satan will neither harm it nor be given power over it."