HARTFORD, Conn. (AP) – A conservative group opposed to same-sex marriage told the state Supreme Court Feb. 9 that it wants to present evidence that it says shows children are hurt by living in gay and lesbian homes.

The Family Institute of Connecticut wants to intervene in a lawsuit over whether same-sex couples should be allowed to marry. The group says Attorney General Richard Blumenthal, a Democrat, isn’t vigorously defending Connecticut law, which defines marriage as between one man and one woman.

Blumenthal said he was vigorously defending the law.

The lawsuit was filed by eight same-sex couples who claim Connecticut’s marriage laws are unconstitutional because they treat same-sex and opposite-sex couples differently. The Gay and Lesbian Advocates and Defenders, a group involved in the case, used a similar argument to win same-sex marriage in Massachusetts.

The Family Institute has already filed a brief in the case but urged the Supreme Court to let the group question witnesses and present evidence that same-sex marriage is bad for children.

“Not arguing about what’s in the best interests of children is essentially conceding the case,” Brian Brown, the group’s executive director, said after the arguments.

Attorneys for GLAD and the couples say the institute has no standing in the case. Allowing the group to intervene, they said, would allow any group with a strong opinion to enter cases.

Ben Klein, a senior attorney with GLAD, said the studies the Family Institute wants to present are misleading. He said they focus on children in single-parent homes, not on children raised by same-sex couples.

“It’s a red herring,” Klein said. “The FIC is an ideological advocacy group. They’re not scientists.”

Lawmakers recently approved civil unions, making Connecticut the first state to offer them without a court order. But GLAD and the couples involved in the lawsuit argue that civil unions are not equal to full marriage.

The two sides argued before the high court for about an hour. No decision was released. They’re due to return to court March 21.

Janet Peck of Colchester, a plaintiff who has been with her partner, Carol Conklin, for 30 years, said she just wants the case to move forward.

“I’m hoping that we get a positive ruling so that we can move on to what’s really important to us, getting the right to marry,” she said.