How can you be too young to be able to give consent yet old enough to be culpable for rape?

BBC News - Boys aged 10 charged with raping eight-year-old

Two 10-year-old boys have been charged with raping a girl in west London.

Each faces two counts of attacking a female under the age of 13 following advice from the Crown Prosecution Service, the Metropolitan Police said.

They were arrested after an eight-year-old alleged she had been assaulted while playing in a park off College Way, Hayes, on 27 October.

The pair, who cannot be named for legal reasons, are due to appear at Uxbridge Magistrates' Court on Thursday.

Police were called by the girl's family after she returned home from the park.

Officers from the specialist Sapphire Unit, which investigates allegations of rape and sexual assault, have been dealing with the case.

http://news.bbc.co.uk/1/hi/england/london/8417317.stm