Baby’s Parentage Questioned in Suit : Custody case: Lawyer for surrogate mother says he can’t be certain of client’s biological link to child without medical proof.

A lawyer for an Orange County surrogate mother fighting to keep the child she is carrying cast doubt Friday on the baby’s parentage.

Richard C. Gilbert told a Superior Court judge that until he obtains medical proof that his client, Anna Johnson, is carrying a baby created from the egg and sperm of the purported biological parents, Mark and Crispina Calvert, he cannot be certain of the child’s parentage.

“We don’t know for sure whose sperm and egg are involved here until tests are done,” Gilbert said after a court conference in Santa Ana. “The only biological link that’s been established is Anna’s, because we know for a fact she’s the birth mother. Anything else, we’re not sure of.”

Gilbert said he cannot rule out the possibility that Johnson became pregnant on her own around the time she was implanted with a fertilized egg at UCI Medical Center in Orange on Jan. 19. But he would not indicate whether Johnson, who is due to deliver in mid-October, was involved in a sexual relationship in January, saying he did not want to violate her privacy.

Johnson sued the couple last month, asking a judge to declare her the biological mother of the baby and award her custody. She claims the Calverts neglected her during pregnancy and would make unfit parents, an allegation the Calverts deny.

Johnson’s lawsuit is the first in which a surrogate mother with no apparent genetic link to the baby is asking to be declared the child’s mother.

Robert Walmsley, one of the Calverts’ lawyers, said that if the baby is the result of a sexual liaison Johnson had, the Calverts would lose any legal claim to the child, because they would bear no biological relationship to it. But the Calverts will sue Johnson if tests show she is not carrying their child, Walmsley said.

“They would have a tremendous case for fraud,” he said. “She’s been leading them along all this time, saying she was carrying their baby. She’s never disputed that before. They’ve paid her thousands of dollars. We’d sue her for the emotional turmoil she caused and to get that money back.”

Walmsley said that Johnson had been having a relationship with a man that ended only a short time before the in-vitro procedure was performed. But he said he and the Calverts relied on Johnson’s written promise that she would not engage in sex with anyone during that time.

Walmsley said he will try to have genetic tests performed as soon as possible, but Gilbert contends that will not be medically safe until after the baby is born. Doctors will assess that question. But Walmsley said Gilbert’s argument shows that he raised the issue “only as a delaying tactic” to put off arguments over who will get custody.

None of the doctors who performed the in-vitro fertilization could be reached for comment Friday. But Walmsley said that if Johnson became pregnant as a result of the laboratory procedure--and not through intercourse--he is “very confident” that the fetus in her womb is the Calverts’.