After the war everyone heard the Wireless, Kingsley and the Remaining Unspeakables came forward and told the world of some findings about: Magic had decided the Wizarding World needed a population boom and was seeking to force it to happen, everyone's Sex drives were out of control.
Now everyone could have sex anywhere and anytime as long as both sides agree to it.
Everyone is Horny all the time, Harry is single, Ginny is dating someone else.
Harry getting someone pregnant the very first time, they are horny they aren't idiots and so they have contraceptives,
