I would say it’s a mix of a) audiences being more comfortable with male nudity now and b) women having more power on set to say what they are and aren’t comfortable with.

Because of things like the Me Too movement, there is a shift now with women speaking up if they’re uncomfortable with certain things on set, as well as intimacy coordinators becoming a common thing. Like it or not, women are likely to face more publicity, backlash and disturbing fan interactions if they go fully nude on screen, especially on popular shows. I would surmise more are opting out of going nude to protect themselves from unwanted attention. Emilia Clarke in GOT refused to go nude in later seasons, Ana de Armas recently came out saying she worried what response she’d get from her nude scenes in Blonde. Sydney Sweeney has talked about feeling less respected for her acting because of what she shows of her body on screen, and asking Euphoria’s creator for less nudity unless it was necessary to the story. While in the past they may have been more hesitant to speak up, there are systems in place nowadays to ensure actresses are comfortable in the spaces they perform in. And if there’s no need to do it, then why would they?

Also, a lot of male nudity on screen uses prosthetics these days so that’s one thing. But I also think men are more likely to go full-frontal because their nudity isn’t as “sexualized” as the women, and they can get away with it (mostly) without much media attention. It’s a brave thing to do, and I think it’s great if it’s serves the story but we should never expect anyone to go nude if they’re uncomfortable with it.