Then, frankly, that manager is an idiot.
There are men who "shouldn't be in IT because they're not as analytical, careful, too emotional, etc" as well.

Truthfully, I think a lot of it goes back to the old "there are certain things that are "boy" things, and certain things that are "girl" things, and never the twain shall cross."  Which is BS.  I'm not going to pull out the (arguably false) chestnut of "you can be anything you want to be" (after all, I can't be an astronaut, or a politician (I can't lie convincingly and I still have a soul,) or a professional baseball player) but there is no reason whatsoever that a woman can't be an IT person of any stripe (server ape to developer) other than people trying to steer them away from such positions because "those aren't jobs for girls."  It's the same thing if a man wants to do something like daycare or nursing (although I'd bet there's still far less pushback from people for the guy.)

I recall seeing some comments elsewhere about the "Women in Technology" discussions, and why they're "sexist" and seemed to show that women need to be treated differently then men.  Well the problem isn't that women need to be treated differently, it's that men need to STOP treating them differently.