In a saga that tests the understanding of modern science, judicial fairness, and the rights of gay and lesbian parents, two lesbian mothers are fighting over who should get custody rights of fraternal twins that both women helped bring into the world, and both participated in raising until their relationship went sour.

The two women, identified only as K.M. and E.G. in court documents, met in California in 1992, moved in together in 1994, and registered as domestic partners in San Francisco. The couple wanted children, but had a problem: E.G. was having trouble producing eggs. Because of fibroid cysts on her uterus, K.M. couldn’t carry a child to full term.

The solution they came up with seemed the perfect mix of biology and love: K.M. would offer her eggs for fertilization, and E.G. would carry the children in her womb.

But while waiting to have her eggs harvested at the fertilization clinic, K.M. says she was handed a stack of documents to fill in and sign. Things like her medical history. Without realizing it or thinking much about it, she says, she also signed a form waiving her rights as a parent. Such a form is typically used to thwart legal battles in cases where a woman offers her eggs to a heterosexual couple that cannot have children of their own. The director of that clinic (who was not there when E.G. and K.M. sought to produce children) now says that such a form should never be given to a lesbian couple, and has done away with it.

That form didn’t seem to matter much initially. When the babies were born a month prematurely, both mothers stayed by their bedside round the clock in the hospital. As the babies turned into toddlers and then young kids, they called both women "momma."

But in 2001, the love that K.M. and E.G. once shared faded. E.G.—the birth mother—took the kids and moved to Massachusetts, and continually tried to cut out K.M.—the egg-donor mother—from the children’s lives.

In an earlier court decision, E.G. won full custody rights to the children, based solely on the waiver form K.M. signed while waiting to donate her eggs. Luckily, an appeals court will hear the case again. It should consider more than a hastily signed form that should never have been presented to a biological parent anyway.

For her part, E.G. continues to claim that she never intended to share parenthood with K.M. In court, she testitifed: "I told her [K.M.] that I would not be willing to consider an adoption until five years after the children were born because I didn’t know her well enough."

This is a remarkable statement that seems hard to believe. E.G. was willing to move into a house, trade rings, register as a domestic partner, and bring children into the world—all with someone she didn’t know or trust? If that is true, it begs the question of just how fit a mother E.G. is, allowing a virtual stranger to help raise her kids for six years.

The truth, of course, is that both E.G. and F.M. are the mothers of their children—in the biological sense as well as the sense that matters most, the sociological sense. Both women participated in the births and rearing of these children for more than six years. The mere fact that the two women are no longer a couple cannot erase the history or importance of the ties the children have with F.M.

Thankfully, an appellate court is set to re-hear the case. "We’re hoping the [new] ruling advances the law so that the children of gay families have the same legal protection as the children of heterosexual families," Jill Hersh, K.M.’s attorney, told the Los Angeles Times. On appeal, the court should consider the real life circumstances of this couple, and grant F.M. the joint custody she deserves of her children.

But this tale is more than one of scientific interest and domestic wrangling. It carries with it an important message to those of us in the gay and lesbian community—especially as we fight so hard to have our relationships recognized and valued.

It is particularly unseemly that E.G. is leaning on circumstances and rules that disadvantage gay and lesbian parents in order to deprive F.M. of her rightful place as a lesbian mother. That is even more galling in light of the fact that our movement is now more than ever engaged in a fierce battle to win recognition and value for our relationships.

As gay and lesbian people, we cannot clamor for the marriage rights that would legally equalize our relationships, and yet refuse to act fairly in the analogous circumstance of divorce.

In all senses of the word, F.M. is a mother to her two children, and neither societal prejudice against her as a lesbian, nor personal malice against her from E.G., should prevent her from being re-united with her kids.