I don't really cotton to the concept of sisterhood. I know women who were taught by their mothers to flirt, who treat their sons like kings and their daughters like suspects, who think of me as some kind of alien. Sisterhood doesn't play much of a role in my relationships with them. Sure, if a lady who only became such physically in her twenties started likening her childhood experiences to mine, I'd scoff (and probably suggest hers were probably tougher), but I wouldn't have any trouble accepting her as a woman now. Hell, I don't have trouble accepting committed transvestites as women. Silly women, in my view, since they seek out the very trappings of femaledom that I reject, such as heels, makeup, and push-up bras, but women nonetheless.
In sum, sisterhood, schmisterhood.