The big day had come.
Newborn twins Sarah Estelle and Anna Isabelle McLaughlin lay in bassinets beside their mom in St. John's Mercy Medical Center.
Anna slept. Sarah's wide, dark eyes took in the lights and shadows of the room. She was so little. So perfect. But her new life was already so very complicated.
Jen McLaughlin, of Kirkwood, Mo., snuck her daughter a tiny kiss.
"How can you just look at her and not think she could have been left on a shelf to perish or be handed over to stem cell research?" she asked.
An estimated 500,000 frozen embryos are stored nationwide as the byproducts of advanced fertility treatments, commonly known as in vitro fertilization, or IVF. Although most who create the embryos will use all of them in an attempt to have a child, sometimes there are extras. Anna and Sarah were once two of them.
Last winter, McLaughlin and her husband, Pat, were given the twins' embryos from a couple in California who had successfully birthed a son. With two children already, their family was complete.
But the California couple never anticipated that four frozen embryos would remain -- scant specks in glass pipettes, each about a hundred cells in all and visible only to a microscope.
The McLaughlins are among at least 260 families nationwide each year who successfully have babies after embryo donation, sometimes called embryo adoption.
In the process, the couple have plunged headlong into the dicey ethical, religious and medical debate over the creation and fate of frozen embryos.
It's a debate that McLaughlin, who is Catholic, has tackled with total certainty, grounded in a belief that the embryos are moral equivalents of children. The embryos, too, needed a family.
Her conviction about the sanctity of family is also firm. So much so that McLaughlin and the donors are pushing the bounds of a simmering ethical debate on embryo donation even further by rethinking what "family" really means and just how far their children's genetic bonds should go.
Embryo donation sometimes is an anonymous process, with donors and recipients engaging in a cloaked transaction through fertility labs that severs the likelihood of a future child's linking to a genetic past.
But these two couples insisted on an open process so the genetically related children -- even the children who still may be born from the two remaining frozen embryos -- would stay connected. They felt their children had a right to know their genetic heritage, no matter if their full and half siblings are raised by different parents in different circumstances and most did not come from the same womb.
"He's going to have that richness of knowing everybody's there, we all care about him and we all know him," said the embryo donor, who asked not to be identified to protect her son's privacy.
And the children's history is even more complicated, because their embryos were created using eggs from yet another donor. The egg donor, too, has her own two children, linking the children born from the embryos to even more half siblings.
The branches of this high-tech family tree, germinated under a microscope, could potentially bear nine genetic full and half siblings living in two states, if not more, 2,000 miles apart.
If this all sounds like untested waters in family dynamics, it is.
"It's a brave new world of assisted reproduction," said Paige Cunningham, executive director of the Center for Bioethics & Human Dignity, based in Chicago. "After all, we're just experimenting here, aren't we?"
McLaughlin had no luck carrying a pregnancy to term, and she and her husband wanted a big family. So they decided early in their infertility problems not to risk valuable time on uncertain treatments.
They embraced traditional adoption. By the time the McLaughlins learned about embryo donation in 2008, the couple had adopted five children, four of them from Russian orphanages and one from Missouri.
McLaughlin, however, never lost the intense desire to have a successful pregnancy of her own. When she read a short newspaper article on embryo adoption -- where the embryo exchange is treated more like a traditional adoption -- she knew she wanted to try.
In IVF, a woman's eggs are harvested and then fertilized by sperm in a laboratory. The fertilized eggs are allowed to divide into a tiny cluster of undifferentiated cells. Some are usually transferred to a womb that has been coaxed by a regime of fertility drugs to encourage implantation and a successful pregnancy.
Others are sometimes frozen instantly in liquid nitrogen to be thawed and used later for another try or more siblings down the line. But sometimes viable extras remain. If cryopreserved correctly, they can theoretically exist forever.
The fate of those frozen embryos not only sparks intense ethical debates over when life begins, but overlaps with the polarizing issue of embryonic stem cell research, which proposes using embryos to find potential cures to disease, over the opposition of many abortion opponents.
The concept of donating embryos to other couples got a push eight years ago under President George W. Bush, who dedicated federal funding to promote, in his terms, embryo adoption. The federal funding has since increased to $4.2 million. Now, Georgia has passed the nation's first state law symbolically recognizing embryo adoption.
Yet calling the process "adoption" raises intense debate. The American Society for Reproductive Medicine argues that such transactions should strictly be called donations. Arthur Caplan, head of the Center for Bioethics at the University of Pennsylvania School of Medicine, said equating embryos with orphans or foster kids denied the grave needs of the world's existing children.
"If you have to make a moral choice between adopting a baby or an embryo, is it really possible to say there's no difference?" he asked.
Even the Catholic Church, which believes the embryos are people, doesn't condone most assisted fertility treatments and has stated that it neither accepts nor rejects embryo donation.
McLaughlin ultimately realized her decision wasn't going to please everyone, but she believed what she was doing was right for her and the embryos.
From the moment McLaughlin decided to attempt embryo donation, she also knew she wanted to keep the process open. She chose a donor exchange service called Miracles Waiting, one of the few places where donors and recipients can meet without predisposed religious principles or complicated adoption terms imposed on them, said the organization's executive director, Kim Walton.
"Because this is such an emotional subject, it really takes them deeply into, or possibly away from, their religious beliefs," Walton said. "Everybody's having a hard time; there's no reason to judge them."
McLaughlin nearly jumped out of her seat when she first read the donors' posting. The couple had four embryos that had been conceived with donor eggs from a woman with a Russian heritage. That excited McLaughlin, given she and her husband had adopted four children from Russia.
After many conversations and a home study, the deal was struck last February through a property contract that included clauses requiring future contact between the families. The McLaughlins covered legal costs and medical expenses as well as fees to keep the embryos frozen.
In May, when her hormone levels were just right, McLaughlin ducked out of town for the transfer of the embryos into her womb.
McLaughlin has never shied away from knowing her adopted children's pasts. She and her husband, a lawyer, had spent thousands of dollars on private investigators to track down the birth families of their adopted Russian children. They knew their kids would one day wonder about who they were.
The embryo donor, 46, was also a firm believer in open adoption. She had been adopted as a young child and had only recently reconnected with her birth family. "You're just completely cut off from a part of you," she said of closed adoption.
So the embryo donor family invited McLaughlin to stay with them in California for the embryo transfer. It was the beginning, all of them hoped, of an important lifelong connection. McLaughlin stayed with the donors for a week. The couple drove her to the fertility clinic and even helped with her needed hormone shots.
When McLaughlin returned from California, she was glowing. She was pregnant, and she had spent time with a blond, blue-eyed little boy who was her daughters' genetic sibling.
McLaughlin was also excited about a new connection. The woman who donated the eggs used to create the embryos was now willing to have limited contact with her genetic offspring's families.
All of the adults involved know there are emotional hurdles ahead. Their children one day will deal with the knowledge that they have connections to at least a dozen full, half and unrelated siblings, as well as distant genetic parents.
"It's impossible not to ask how these children will feel knowing we gave them away," the embryo donor said. "We had to ask, how would they feel knowing there's siblings we didn't keep?"
Social scientists also aren't sure what may come of this. While research suggests open adoption is healthy in traditional circumstances, there is no research on how embryo adopted children may fare in open arrangements. And some worry that parents are imposing sibling relationships on the children without first giving them a choice.
That concern is shared even by some conservative groups that encourage adopting embryos but condemn the technology that made them.
"My concern always in these cases is the adults who are creating all of these confusing relationships, and the way they do it fairly nonchalantly," said Barbara Quigley, executive director of the Center for Bioethics and Culture Missouri.
McLaughlin says it's all very simple when you look into the sleeping faces of her twins.
"People are going to look at their photos and agree this is the right thing to do," she said.
All the studies in the world also aren't going to change the embryo donor's convictions about open adoption and donation.
"I think that most people who are researchers have never been adopted," she said. "If they haven't had that experience, they couldn't possibly know what it was like."
So, with tiny baby steps, everyone is moving ahead in this most modern of families, linked genetically and contractually, potentially for a lifetime.
In late January, a small package arrived on the McLaughlins' doorstep. The package contained two polka-dotted bath towels embroidered with Sarah's and Anna's names.
They were a gift from the twins' original egg donor, whom McLaughlin has yet to meet.
"It felt like a miracle," McLaughlin said. "I felt like everything was coming full circle. These girls are going to have a connection with all of their different mothers."