Have you considered that he may have some (treatable) mental issues? Having mild forms of autism, for example, can leave one pretty impervious to the effects of what they say. "He's just a jerk" doesn't seem like the right message, given all you say.

More ideas: Are you the only one singled out? Do you "stand out in the lab" for gender or race (etc) reasons? Other women in the lab? How are they treated? How do others feel ("Oh that's just Buffy being Buffy")? Does anyone feed it right back at him?

Still more: Some people are very insecure if they judge a student is possibly brighter than they are. The movie Good Will Hunting gives a good example of this.

I would not bring "male vs female" gender into it either since there's no evidence to support that and the PI cannot present their side.

No, I never said that he was sexist. I just meant that there are differences in how two males speak to one another versus a male and female. Sorry for giving off that vibe. Also, I am not trying to demonize him. I like him. I just wish he would not embarrass me like this in front of my colleagues.

@JobHunter69 (Since I cannot silently downvote your comment) A person with normal social skills and empathy might tease someone, but would quit the teasing if it is not reciprocated. Even more so if it's a direct subordinate in a professional setting.

Since there is no way to ask your PI, we have to assume that he is right and you are wrong. At least he does not complain about you on SE.

@dodd are you a faculty that does similar things to his students? because you sound like you are personally offended :)

@CoderInNetwork: I am not offended. But the OP accuses an unknown person without giving him a chance of explaining the situation. Why should we trust the OP? Most probably he is either lying or tells only a small part of the truth. Isn't it the simple common sense?

How is it "accusing" someone when the identities are hidden? It doesn't make any sense to me. You are here to help the OP solve her problem based on the available information, not to cast judgments on her. She is not on trial. You either can help her and you do, or you can't and you just simply stop being judgmental and offensive (and you move on with your life).

@dodd, all -- I think we have to be careful before we accuse people of "lying" or not being "useful enough." One of the challenges of this medium is that we always have one side of the story; assuming that advisors are always right and students are always wrong is definitely not our policy. In any case, this discussion has gone way beyond "seeking clarification or suggesting improvements", time to move to chat.

@dodd Instead of calling someone right or wrong, or even a liar, you could could omit your judgement and simply stick with the fact that the OP could be presenting an incomplete picture, whether they are aware of it or not.