One of my coworkers, when he thinks people aren't doing a good job, calls them ladies or girls. He also doesn't listen to the women on our team, insists on pair programming with them if he has shared assignments with them instead of splitting those assignments into subtasks like he does with the other guys, and is in general a nice dude to the other guys and treats the women like they're junior. If the rest of the men on the dev team behaverd like that, I honestly bet there would be no women on our team. I'm not sure how to approach him about it, but the women we work with don't seem to want to take assignments with him or interact with him, for fairly obvious reasons I guess.