merman, male mermaids, get pregnant like seahorses and both males and females can get them pregnant. Both mermaids (females) and merman (males) can get pregnant. Greg was a merman and he was pregnant with a litter of seven. his vent (the little flap below his belly) turning the same color as his stomach as an indicator. He is obviously feeling the first tension in his back and will probably have strong contractions soon.