Responses
No you are absolutely right, it's not like eggs have motility like sperms, so I'm guessing it's the women who have some kind of mutation that let's her eggs flow all the way to the penis.
They are probably alien species called hetro sapiens
I'm not really bothered by mpreg coz I absolutely love it, but how do men get pregnant when they're with a woman? Like, do the eggies enter their penis?
Sorry, don't mind me (=・ω・=)