By Francis Markus BBC, Shanghai

The answer, at least in southern China's Guangdong province, seems to be headlines like: Sex in Private Cars Causes Concern.

Police say they can only ask couples to go away

It has been happening by night at scenic spots and police are quoted as saying there is little they can do about it.

This is an interesting new phenomenon in our society, says one local lawyer quoted by the official Xinhua news agency.

Apparently it is also an area where the law is impotent.

The lawyer describes the car as a private space, where the owner can exercise his or her human rights.

Police, not known for their shyness on many matters, say there is nothing they can do but ask the couples to go away.

The reports come at a time when sex is making the headlines in Guangdong. A local columnist has caused a nationwide sensation by publishing a web log detailing her encounters with dozens of men.

She became the latest in a series of writers on risqu� subjects to have her book banned.