Nigel, I suspect there are a lot of girls who'd have crushes on a 22-year-old male teacher (or older, for that matter). It's not a one-way street.
I don't actually see that there's anything wrong with this if both sides are consensual, but there's *so* much scope for coercion that it's massively unprofessional. If you really need to have a relationship with someone you're teaching, then you stop teaching them. In many larger schools it'd be perfectly possible to move the kid to a different class, or for the teacher to swap with another teacher.
Nigel, your point is a completely different one, which is whether men are encouraged (or "allowed" by society) to do particular jobs. Or even if they know those jobs exist - a couple of years ago I went for physio at Addenbrookes (one of the larger hospitals in Britain), and you wouldn't need both hands to count the male physio graduates over the last 30 years against over a thousand female graduates. Nor has there ever, in Britain, been any effort to attract men to childcare. The other way round, my engineering course had 5 women against 75 men, and there is *major* funding going into improving this ratio. I completely agree that this is unjust, and it makes me very angry.
But in this case, there actually *is* sexual equality going on - an older woman doing this is held responsible under the same laws that you'd more usually expect to be guarding against predatory older men.