According to guidelines drawn up by, of all things, the Institute of Physics the following words and phrases should be avoided to prevent sexism.
Sissy
Don't be a girl
Man up
Cupcake
(Senior teachers will be appointed ‘gender champions’, in a bid to eliminate gender stereotyping.
I would suggest they add, "grow a pair" and "you throw like a girl" to that list.
In all seriousness, the idea is that schools should find strategies to get more girls to study so-called ‘male’ subjects such as economics and physics at GCSE and A-level, while boys should be encouraged to take more ‘female’ subjects including English literature, foreign languages and psychology.
Hang on! Male subjects and female subjects - now that is sexist. The Department for Education obviously has a lot of time on its hands, and a slightly worrying regard for physicists.)