In Taiwan, genetic tests have been on the upswing, particularly in the past couple of years due to stricter regulations that often require DNA analysis reports for purposes such as household registration of minors, notes Dr. Yi-Ning Su, director of the National Taiwan University Hospital's Cytogenetics and Molecular Genetics Laboratory.

Su, who has been with the hospital's medical genetics department for about seven years, has seen his fair share of peculiar cases.

"Especially when it comes to paternity testing, while some parents come to us already with some doubts, every once in a while we still see cases where couples are completely taken aback by the results," he says.

Out of the 700 to 900 sets of couples or families that undergo genetic testing every year at the hospital, about one or two per month are surprised by paternity test results, according to the geneticist.

The doctor recounts that one of the more memorable cases he has witnessed occurred about three years ago, when a Taiwanese man and his foreign spouse went in for a routine paternity test required for their six-year-old son's household registration so he could be enrolled at school.

"Not only did it turn out that after six years of raising the child, the boy was not his, but the mother disappeared without a trace even before we could deliver the results," Su noted. "So the child became an orphan. We had no clue where his biological family was."

"We were, of course, very shocked. For her to just take off like that was very sad," he lamented. "What we suspect is that the mother probably already knew."

"We later learned that the father, who was an only child, had divorced his first wife before because she was unable to bear him male children," continues Su. "We often wondered if the second spouse, aware of this pressure, switched a female baby for the boy while still living abroad."

While cases like these are unfortunate, other times genetic testing can uncover much-welcome results, as is the case with local couples who share the same last name and wish to be married -- traditionally considered taboo in many Asian societies."Some of the older generation in Taiwan still frown upon marriages between a man and a woman with the same surname for fear that they may be somehow related," says Su. "But this belief is completely wrong," the doctor stresses.

"Even though nowadays the younger generations are not concerned about this taboo, every month, on average, we still see one or two couples with the same surname who, under pressure from their older generations, get tested before they get married to prove that they are not related," he points out. "The results virtually always come back negative for blood relation."

"Couples who are in fact consanguineous almost always already know it, and come to us not so much for testing, but for genetic counseling to find out if there would be any problems with their offspring," he says.

Other cases have also raised many an eyebrow at the medical genetics department.

"A man once brought his bedsheets because he suspected his wife had committed adultery when he was away on a business trip," Su recounts.

"Some people have brought human ashes, or asked us to extract specimens from cadavers to determine biological relation for legal entitlement purposes," he offers as other curious requests.

"While it is possible to use such samples to conduct genetic analysis, we do not normally perform these types of forensic tests as they fall under the realm of the Criminal Investigation Bureau," he explains. "We do not carry out tests without consent of the individual, although we will perform them only in the case of court orders."

Asked by The China Post whether there have been cases in Taiwan of twins with different fathers, a rare occurrence that has been known to happen in the case of fraternal twins, Su says that although theoretically possible, he has not heard of any such cases in Taiwan. "At least in our testing we have not uncovered this."

"Of course, as it is often the case, the mother is the only one who knows best," he adds with a smile.