Didn't we have a thread like this a few months ago? I think I remembered saying that one of the "charms" of those jerks in the Snakemen clan was that they were such... jerks. They were a bunch of zenophobic/racist sexist male chauvenist pig-snakes. That's what was so great about seeing them get beaten up - they deserved it!
I don't think that women - even snake women, would have held any place in the Snakemen army. They would've been ridiculed. And probably eaten...
Also, I always had the idea that the Snakemen were magical in their being and so "reproduction" as such was more or less something that King Hiss handled. Kinda something like stirring up more warriors from a magic cauldron or the like... I just find it very hard to imagine procreation between snake people, to say nothing of the fact that no female snakeman character has ever been represented in either the mini-comics or both major cartoon series.
So even if they did exist, you can bet that those jerks would have delegated them to be slaves or mere servants at best.