From Laban Tall.
A seventeen year old is ...A 'child' to be protected, if fighting for his country.
A 'man' if being sodomised.
A 'child' if engaging in prostitution. As the Association of Chief Police Officers point out "The Children’s Act makes it clear that young people are children if seventeen years or under".
A full adult capable of voting (but not of taking on any other adult responsibilities such as being imprisoned with adults if convicted of a crime, supporting oneself etc).
A child to be protected from the dreadful consequences of smoking.
I think there's some kind of pattern here. I just can't quite work out what it is.
Just like a baby is a foetus if being aborted, but an unborn child if mummy is having a crafty fag.