Yes that's so true, if fems are made with a solid non "hermie" female then the resulting beans should more than likely be "herm" free! Most breeders selling f'ed up fems are usually the ones who are quick to rush these "elite" clone only strains/crosses out to the masses to $$$$$ in off the hype .....the OGs, GSC, and a few others come to mind (.....we already know the Glue is next lol!) Femming a "herm" plant and selling the beans for up to or more than $200 is fuckin' bullshit!!
Sometimes the genetics do play a part in it but most of the time people see "herms" in their garden they have more to do with em! Now that's a hard pill to swallow for many of these self proclaimed master growers out here nowadays lol, not every plant grows alike or likes the same conditions that's one of the reasons I don't grow hydro. The soil you use, your enviro, nutes, etc, etc it's all about finding the plant's sweet spot and not pissing it off!
Most of the time when you find sacs on your gal try to trace back a week or two, I'll bet the barn something happened in that time frame to cause them ....remember now cannabis plants #1 goal in life is to produce seeds, not sinsemilla, it's all about survival and that's a mechanism/trait that probably shouldn't or never will be bred out!