According to the classic article on that topic, it's exactly that kind of comments that contributes most to the discomfort of women in male-dominated groups:
Sexist jokes are the number one way to drive women out of any group, and they are more common than many people realize.
[...]
Sometimes he tells me that it's okay to make a sexist joke if it's true, or it's funny (funny to whom?). What some people fail to realize is that jokes about gender of any sort almost always make fun of women, and will make most women angry, regardless of the context. It doesn't help to first make a sexist joke about men and then one about women.
[...]
your comments and jokes are driving women away. If that's not what you want, then don't make sexist jokes. If you're not sure if your joke is sexist, find something else to say.
Sexist jokes are the number one way to drive women out of any group, and they are more common than many people realize.
[...]
Sometimes he tells me that it's okay to make a sexist joke if it's true, or it's funny (funny to whom?). What some people fail to realize is that jokes about gender of any sort almost always make fun of women, and will make most women angry, regardless of the context. It doesn't help to first make a sexist joke about men and then one about women.
[...]
your comments and jokes are driving women away. If that's not what you want, then don't make sexist jokes. If you're not sure if your joke is sexist, find something else to say.
[http://tldp.org/HOWTO/Encourage-Women-Linux-HOWTO/]
(The title suggests that the article is just about LUGs, but it's really about the whole computer-tech scene.)