To GW's credit and I mean this in the most CRITICAL support way possible, they do seem to be slowly working up the courage to bring back female marines
- They gave the Primarchs a mom
- They introduced female Custodes
- One of Fabius Bile's creations is a female SUPER-totally-not-space-marine who can rip the head off regular marines barehanded
They really need to rip the band-aid off and ignore the chuds