It's hardly surprising, most if not all cervical cancers are caused by viruses, so starting unprotected sex earlier means the chances of the girl being exposed to the virus is higher. It didn't mention in the article if they'd normalised for smoking as less affluent people are also more likely to smoke (which is another risk factor).

But the number of sexual partners a woman has and smoking did not account for any of the difference.

Study leader, Dr Silvia Franceschi, said the findings were not restricted to adolescence and the risk of cervical cancer was also higher in women who had their first sexual intercourse at 20 rather than 25 years.

What do you make of that then?

20? 25? Bloody hell. I didnt know there were any virgins that old. Arent they all round the back of the bike sheds before their 14th birthday nowadays!