HARRISBURG -- In a case that bioethicists say could have wide implications, the state Superior Court invalidated a verbal agreement between a woman and her sperm donor and ordered him to pay child support for twin boys born nearly 10 years ago.

A three-judge panel said the deal between Joel L. McKiernan and Ivonne V. Ferguson that he would not be obligated for any child support was "on its face" a valid contract, but it was unenforceable due to "legal, equitable and moral principles." Previous state appellate rulings had determined that parents may not bargain away a child's right to support.

"We agree with the trial court, 'although we find [Ferguson's] actions despicable and give [McKiernan] a sympathetic hue, it is the interest of the children we hold most dear,'" wrote Senior Judge Patrick R. Tamalia in a ruling issued Thursday.

The decision should give pause to sperm and egg donors who expect anonymity, said Arthur Caplan, a professor and medical ethicist at the University of Pennsylvania.

"Anybody who is a sperm donor ought to understand that their identity could be made known to any child that's produced and they could be seen by the courts as the best place to go to make sure the child has adequate financial support," Caplan said yesterday.

Ferguson and McKiernan met at work and had a two-year affair that had "waned" by late 1993, when Ferguson persuaded him to act as a sperm donor with no responsibility for any child born as a result, according to the trial judge's written opinion.

Ferguson, who separated from her husband in 1992, maintains that McKiernan was a willing partner in the in-vitro fertilization.

The twins were born prematurely in August 1994. Ferguson filed for support nearly five years later.

McKiernan has been paying up to $1,520 a month in support since losing the Dauphin County case. Since the twins were born, he has married, had two children and moved to the Pittsburgh area.

"Obviously I'm not happy with what occurred, but I don't want to comment any further," he said. His lawyer, John W. Purcell Jr., said he may appeal to the state Supreme Court.

"The cautionary tale is you can't trust anybody any more," Purcell said.