Bitch: a sexist insult or a sex-specific insult?

Either a woman or a man could be born illegitimately and this be in a literal sense a "bastard". But I'd call it very unlikely that you'd ever say to your best mate "My boss is a total bastard" if your boss were a woman. Likewise you wouldn't call the female boss an asshole/arsehole. There's no logical reason why not, but I just don't think anyone would do it. In a way it's like a lot of other things in life, where we assume everything important is done by men, and then we have to make it clear that once in a while we're talking about a woman.

I think both bitch and bastard, in their 'old' meanings are sexist towards women. Bastard is an insult to your mother - a woman who had sex and got pregnant out of wedlock. Bitch (according to my grandmother, who is horrified by the term) means a prostitute. In fact, it kind of has come back to a similar meaning through rap music.

The modern meanings of bitch are (according to me; I didn't look it up in The Combined Feminist Rule Book and Dictionary):

1. the same as bastard (cold hearted/mean), so that isn't sexist.

1. A person who makes nasty, gossipy, meanspirited remarks about other women. That kind of criticism is only ever really made towards women, so is sexist.
2. My bitch. This implies you are sexually owned by a man. This is sexist. It is also sometimes said to men, often by other men. This implies both that they are owned and that they are also being accused of being a bit of a girl, so again, sexist.