together ( ͡° ͜ʖ ͡°)
but yeah, it's weird that it only happens to men, but I guess you could say it's because men are more "expendable" in the sense that a guy could get a ton of women pregnant in a short period of time, but a woman can only have 1-8 or 9 babies at a time (world record is birthing 8 or 9 babies at the "same" time, basically same day.) So if it's a thing like mother nature forcing men to leave some descendants behind or die, it would make a bit of sense. But then again, why 18 and not sooner or later, if it's some kind of illness or curse?