Cases involving paternity tests rose 214 percent last year in Shanghai, a report from the city's Pudong New Area People's Court showed, with many disputes involving children born out of wedlock.

In 2010, there were only seven cases of disputed parentage, but that number rose to 22 in 2011, the court figures show.

Paternity tests were first offered to individuals in 2005. In August 2011, the Supreme People's Court ruled in the new interpretation of China's Marriage Law that if a spouse can provide the necessary evidence to prove or disprove a biological parent-child relationship, and the other side cannot supply any counter-evidence, the court could decide in favor of the complainant.

Paternity test results are considered one of the most important pieces of "necessary evidence".

The types of cases also varied more widely last year, the figures show.

For example, in 2010, five out of seven cases of parentage issues resulted from divorce, while in 2011, parentage issues resulting from cohabitation or a change in foster parents were dominant.

Children born out of wedlock also outnumbered legitimate children, accounting for almost 80 percent of all the cases.

Relationship DNA testing labs in Shanghai have also witnessed a "huge increase" since August.

A telephone operator with STRDNA, a Shanghai-based commercial lab offering paternity testing, who spoke on condition of anonymity, told China Daily that calls to book tests have increased from "almost nil or just one a day" to "dozens a day".

But the validity of these paternity tests remains a question. A report by CCTV found that labs of this kind in Shanghai can neither provide any legal certificate that qualifies them to perform such services, nor produce any verifiable, legitimate test results, as the procedure has been greatly simplified in the name of protecting privacy.

By merely providing a strand of hair or a fingernail of both parent and child, the customer of the lab is promised a 99.9 percent accurate paternity test result. Nobody needs to go to the lab in person.

Thee lab charges a minimum of 1,000 yuan ($158) for the service.

Sun Lei, vice-president of the Pudong court, warned against the rash use of paternity tests.

"It's like a sharp weapon. Once used, regardless of the result, it will cause irreparable damage to both the parents and the innocent children. And it's just all because of a spur-of-the-moment lust," said Sun.

Shi Fumao, a Beijing-based lawyer specializing in juvenile delinquency, saw the problem from a wider perspective.

"Studies find that kids from special families, or more precisely, broken families, are more inclined toward misdemeanors and if they lack appropriate parental control, felonies, because of their lack of necessary love and warmth required by every human being," said Shi.

Contact the writer at xujunqian@chinadaily.com.cn