I don’t think they did rule specifically on the constitutionality of an all-male draft.
How many men would declare themselves female if a draft were re-instated? Seems like an easy way out and I don’t think anyone is allowed to question your “choice”.
It came a long time ago and it had to do with ERA.
It was something like since the ERA didn’t pass, women are not eligible.
Research it tomorrow.
Or now. LOL!!!
https://en.wikipedia.org/wiki/Rostker_v._Goldberg