Actually I think this is a fair question. I think it's important to remove barriers and prejudices that prevent any person of a particular sex from being able to go into any field that they choose but I also think it's not straightforward to say that having a 50/50 split always leads to the optimal situation or that if a 50/50 split doesn't exist it automatically means there is some barrier or prejudice. I think it would be much better to focus on making sure that teachers going into the field are competent regardless of their sex.

It would improve teaching the same way it would improve software development: statistically. Talent is normally distributed, across both genders, meaning that external forces that repel one gender from a profession reduces the quality of the talent pool for that profession.