Fathers of Contention

One day in 1997, Michael Lammers received a surprise phone call. A woman with whom the ambulance attendant had once had an affair told him he was the father of her 12-year-old daughter. Like others in his situation, a stunned Lammers couldn't help but wonder whether the child was truly his. So he commissioned a private DNA test and, a few days later, knew for a fact that he was a dad.

While the decline of the two-parent family in Germany may worry traditionalists, it has proved a boon for a growing number of biotech companies specializing in paternity tests....