GEN600 When a person engages in the sex act and his intentions are not for the sake of Heaven, the seed that issues from him is considered a ‘fetid drop,” and God has no part in it.  About such does the Torah say, as in the story of Noah’s generation, “for all flesh had corrupted their way on the earth” [this verse]. This is the way to the destruction of the body, it is equivalent to offering devotions to an idol, or planting a tree that is worshipped by idolators, for he sows corrupt seed.  The offspring of such intercourse become wicked and estranged.  GOODSOC 107