Within the past few decades, the rising rates of IVF, gestational carriers and surrogates have provided new ways for families to form. For lesbian couples, in particular, science now allows for a pretty amazing possibility: reciprocal IVF, a process in which one partner’s eggs are used to impregnate the other.

Also known as “shared motherhood,” this arrangement helps both women play a role in pregnancy—which one couple tells Motherly was such a special gift.

“We just really loved the idea of reciprocal IVF because we would be physically a part of the experience,” says Christina Bailey, who welcomed daughter Kennedy through reciprocal IVF with her wife, Katie.

Initially, Katie and Christina both considered intrauterine insemination (IUI) treatments using a sperm donor. But when they learned about reciprocal IVF, it immediately felt like the best option for them.

“It was important to me to have a child that was genetically mine, while this wasn't very important to Katie,” Christina explains. “Katie liked the idea of carrying a child, so it worked out perfectly.”

As for the final component, Christina says they were able to find the ideal sperm donor for their family through an online bank—which made for another interesting experience.

“We uploaded a photo of Katie's face and it gave results of donors who had similar facial characteristics,” Christina says. “We also looked for someone who had similar interests and talents. For example, the donor we chose has musical talents, similar to Katie.”

But while the decision to pursue reciprocal IVF came easily, the rest of the process isn’t without its challenges.

According to a new study published in the journal Reproductive Biomedicine Online, the reciprocal IVF process isn’t a guarantee: Of 141 IVF cycles tracked, there was a live birth rate of 60% per receiver and a twin delivery rate of 14%.

The expense certainly isn’t negligible, either, with an average cost upward of $16,000 per IVF cycle, according to WINFertility.

As the Baileys tell Motherly, there are also emotional challenges to the arrangement.

“There have been times when people ask Katie if she will have ‘her own child,’ which isn't meant as an insult, but can be taken that way,” Christina says. “The same can go for me with people asking why I don't carry or [they] consider Katie the mother because she gave birth.”

Still, the Baileys wouldn’t have it any other way. Now with another daughter on the way thanks to another round of reciprocal IVF, Christina says it was simply the perfect way for her and Katie to build their family.