I'll admit it's a retcon in the sense that previously it had been mentioned to be a "brotherhood" and such, but who fucking cares. It's just dated lore, and the emperor can do whatever the fuck he wants.
There were in fact female Space Marines in the first editions/Rogue Trader btw. The lore change was based on limitations in early production, which is obvious because the lore reasoning is fucking stupid.
I mean it's not "fucking stupid" to write sci Fi biology to require some arbitrary thing, it's just unnecessary.
Like you could write a book about wizards right now that states "magic is stored in the balls" and we'll, that's your lore. It's a decision that doesn't appeal to the modern world, and I think it's bad writing.
But like, it's all made up. I'm happy they are updating the lore, female custodes looks bad ass and reminds me of Brianne of tarth (spelling) and she was a cool character.
Getting mad they changed something is hilarious, and those voices will fadr away
Ah okay just making sure I wasn't going crazy. I don't know very much about the lore but I do love listening to some long form YouTube videos talking about it