No, I don't mean trans people. I'm thinking mainly of women who, historically, have disguised themselves as men for good career reasons, since they couldn't enter certain professions as women and had no choice. Sometimes women in that situation started relationships with other women, possibly to screen their identity, which is understandable but a bit cruel to their partners. I think this might come into the same category as marrying when you know for certain you can't or won't do what your partner will expect by way of having sex and procreating children. Again it isn't illegal to deceive them in that way, though it's bloody cruel, but I guess it might invalidate any marriage?