NASHVILLE (AP) — Two Tennessee lawmakers want to do away with a 40-year-old state law granting legitimacy to children conceived through artificial insemination. Critics say the bill is aimed at gay couples and their children.

The bill would remove a single sentence applying to child custody when artificial insemination is involved, one that's been interpreted to make no distinction between same-sex and heterosexual couples.

But opponents warn that changing the law could prevent both same-sex parents from appearing on the children's birth certificates, affecting their ability to make parenting decisions ranging from medical care to education.

"It would affect lesbian couples in particular, because if you have two women who are married and one is the birth mother, the other one is presumed to be parent in Tennessee," said Chris Sanders, the executive director of the Tennessee Equality Project.

Ever since the 2015 same-sex marriage ruling, Tennessee laws with gender-specific terms have been interpreted as applying to either gender of married couples. But that would change under another Republican bill that is seeking to eliminate gender-neutral interpretations of "mother," ''father," ''husband," and "wife."

"Clearly, the legislative intention behind both these bills is to stop lesbian couples from having the same automatic recognition of their parent-child relationships that opposite-sex couples have," Julia Tate-Keith, a Murfreesboro attorney specializing in adoption and surrogacy issues, said in a legal memo.

State Rep. Terri Lynn Weaver, the sponsor of the artificial insemination bill, in a Facebook post denied that her bill is aimed at same-sex marriage, and argued it would not de-legitimize children because another state law addresses parentage without asking about the method of conception.

"The remaining law that will now govern the situation does not have the government inquiring into the means by which the couple's child came into existence or whose sperm, the husband's or a donor's, was used," Weaver wrote in the post.

Weaver said there would be no change under her legislation for heterosexual couples. "A child born to a married woman will be considered the child of her husband," she said in a statement.

But that part of the code refers to circumstances when "a man is rebuttably presumed to be the father of a child." Tate-Keith said that that language does not carry the same gender-neutral interpretation as other parts of state law.

Sanders said that heterosexual couples would have to go through more legal steps if the bill becomes law.

"Straight couples will lose the presumption of paternity," Sanders said. "It will require them to go to court."

"What if you didn't tell your family and friends you were getting fertility treatment?" he said. "It just creates more hardship, more hoops to jump through."

Weaver said she is proposing to repeal the law because of constitutional concerns raised by the Tennessee Attorney General Herbert Slatery in a divorce case between two women in Knoxville.

In fact, Slatery's filing in that case defends the constitutionality of the current law, arguing that following the Supreme Court ruling legalizing same sex marriage, the Tennessee statute should not be read as applying to "the legitimate child of the two spouses."

A Slatery spokesman declined comment citing pending litigation.

Democratic state Sen. Jeff Yarbro called bill "an attack on families."

"It's frankly the most ill-conceived and offensive bill I've seen the Legislature," Yarbro said. "And that's saying something."