In the wiki, it says
Mechanics
Unlike the Ebonflame Whelp or the Ebonflame Dragator, this monster is still infectious and has no invasive pregnancy mechanics. It will instead, however, roll for impregnation twice. Infertile or normal male characters may be in for a nasty surprise. If this isn’t to your liking, the cheat “neuter ebonflame” will disable/re-enable the effect. Otherwise, watch out!
What does it mean by nasty surprise? I've tried playing a male, both with mpreg and without, and the loss sex seems to be the same either way.