Originally Posted by
kuronosan
It's called an Oedipal complex when a son is attracted to his mother. Subconsciously, according to Freud, we are all attracted to the parent of the opposite sex and pick our partners based on that parent. It doesn't mean you are really attracted to them and want to have sex with them. It just means on a subconscious level (you are literally not aware that you are doing anything even remotely close to that) the attraction exists.
This is even revealed in the bible. Check the evacuation of Sodom and Gomorrah. In the bible, Lot's daughters are concerned that Lot will have no male heirs since his wife was destroyed by God, so they get him drunk and each take turns having sex with him until they get pregnant.
It's not unusual for the attraction to exist, but under certain circumstances (like hormonal imbalances or pedophilic molesting parents) they do manifest.