Fem seeds may (and there are scientific reasons both for and against this) be more likely to herm in situations that are known to cause intersexing in cannabis, but so will any reg seed with fruity thai genetics in it. To put it in an extremely callous analogy, any parents can end up with a retarded kid, and there certainly hasn't been enough legitimate scientific research on the involvement of genetics in cannabis intersex behavior to have a conclusive opinion one way or the other.
There's tonnes of research on inbreeding. Tonnes. Inbreeding brings good/bad (you find special plants with the recessive traits you want, but you can also easily get recessives you don't want, including lethal ones, if you reproduce with your cousin you have an excellent chance of picking up a lethal recessive, which is why it's recommended you do not do this).
This is why I always try to encourage folks to properly preserve stuff.
When I see people taking one male and one female and pollinating a branch of a single plant and they think they are saving the strain I have to shake my head (since they're not saving the strain and are going to miss many genetic components of the original mom/pop). Anyway, as far as the herm trait goes, that's only one negative trait of many possible. Personally, the chances of me buying an S1 are pretty low for this reason.
Not just herm recessive, but also lethal recessive. I've seen plenty of people wonder why their little seedlings died, what did they do wrong? When they did nothing wrong and it was likely the genetics.
To actually preserve genetics you should take as many plants as possible and open pollinate, by the way.
Not to preach to you, I'm pretty sure you already know this.