In oral arguments Monday, a panel of three judges for the Seventh Circuit Court of Appeals examined whether Indiana discriminates by not recognizing two married women both as parents on their children's birth certificates without having to adopt.

Judge Diane S. Sykes drew distinctions between biological parentage and parental rights, and which of the two should be represented on birth certificates.

"You can't overcome biology," Sykes said. "If the state defines parenthood by virtue of biology, no argument under the Equal Protection Clause or the substantive due process clause can overcome that."

"Your Honor, with all due respect, we maintain that parenthood is no longer defined by biology," said Karen Celestino-Horseman, the attorney for eight same-sex couples who brought the lawsuit against the state for only allowing only a mother and a father to be named on birth certificates.

"That's a policy argument to take to the legislature," Sykes responded.

The state of Indiana is appealing a ruling by a district judge who sided with the same-sex couples and ordered the state to recognize both women as parents on birth certificates of children who are conceived through a sperm donor.

"In our view, that order creates an inequality that did not exist before and undermines the rights of biological fathers and their children," said Indiana Solicitor General Thomas Fisher.

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'Physically impossible'

The couples' case argued that parental recognition should be a benefit conferred by the U.S. Supreme Court's marriage equality ruling in 2015, known as Obergefell v. Hodges.

Prior to the lawsuit, the spouse who was not the birth mother would have to adopt the child, even if her egg was used for the pregnancy. That was the case for Indianapolis couple Jackie and Lisa Phillips-Stackman, who are part of the lawsuit.

Not recognizing the non-birth mother, the lawsuit said, could make it more difficult for families to be covered by insurance policies, or for the parent to enroll her child in school.

The adoption process, which can be costly, amends the birth certificate to recognize adoptive parents. The original record, Fisher said, is still retained.

But the lawsuit contended that spouses should be recognized as a parent when the child is born because of her wedded status — similar to how married opposite-sex couples are often treated, where the husband can be presumed to be the father.

"The statute creates a paternity presumption that just is impossible in a same-sex marriage situation," Sykes said, referring to the state statute on birth certificates that the couples are challenging.

"Your Honor," Celestino-Horseman said, "that's if one still presumes that parenthood is still defined —"

Sykes interrupted: "It's not a parenthood statute. It's a paternity statute. Paternity presumption is impossible in a same-sex marriage situation. So we just don't have any kind of discrimination going on here at all."

Later, Sykes said that what the couples may be seeking is a redefinition of parenthood.

"Your Honor," Celestino-Horseman said, "parenthood —"

Sykes interrupted again: "— is biological or adopted. You want this third category."

As Celestino-Horseman cited relevant cases, Sykes delineated between marriage cases and parenthood cases.

Paternity of a sperm donor?

In pregnancies using a sperm donor, opposite-sex couples can say the husband is the father of the child — but that same presumption of parenthood doesn't extend to a wife in a same-sex couple who isn't the birth mother, the lawsuit argued.

The state of Indiana countered that opposite-sex couples aren't supposed to do that. The mother is supposed to state when the husband is not the father. But that's not what often happens in real life.

"That led me to think that your argument is that a state law becomes unconstitutional because people subject to the state law don't follow it," Judge Frank H. Easterbrook said, "which would be a very difficult position to take."

The debate, he said, would then be about how state law is supposed to operate — not whether it discriminates.

Male same-sex couples?

Easterbrook asked how the couples' case would apply to two married men who have a child through artificial insemination.

Celestino-Horseman indicated the situation was more complicated because it would involve surrogacy.

"I don't want to be the one to tell you this, but Obergefell says there can't be any sex discrimination, and now you're saying there must be sex discrimination," Easterbrook said. "In a female-female marriage, the right answer is mother No. 1 and mother No. 2. In a male-male marriage, the right answer is surrogate mother, sperm donor, followed by adoption. In your view, doesn't there have to be identical treatment of the male-male marriage and the female-female marriage?"

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Celestino-Horseman responded that wasn't part of the case.

"We can't ignore the logical implications of your arguments. And you seem to want to," Easterbrook replied.

He added that the case aimed to require "a mis-recording of who the father is."

"Your view seems to be that it is unconstitutional for Indiana to correctly record the parent," he said.

The Seventh Circuit is taking the case under advisement and may rule at a later date.

Call IndyStar reporter Stephanie Wang at (317) 444-6184. Follow her on Twitter: @stephaniewang.