In 20 to 40 years from now, would-be parents will be able to choose from dozens of already artificially created embryos before having a child based on their preferred criteria and potential, says a bioethicist and author of the book, “The End of Sex and the Future of Human Reproduction.”

Henry Greely, a Stanford University law professor, is the author who sees in ongoing research the future potential to choose children with less potential for future disease, more for athleticism or even a preferred eye color.

“The majority of babies of people who have good health coverage will be conceived this way,” he predicts.

The research Greely points to so far only involves mice in which ordinary cells are turned into sperm and eggs. If such technology can be replicated in humans, Greely believes, most babies would be born using it by the time today’s children are reproducing.

If so, it would mean a woman who wants to get pregnant could produce dozens more eggs without harvesting some of her own ovaries.

Here’s what Greely sees in the future: A man and woman walk into a fertility clinic. The man drops off some sperm. The woman leaves some skin cells, which are turned into eggs and fertilized with the man’s sperm. Unlike in-vitro fertilization today, which typically yields around eight eggs per attempt, the new method could result in hundreds of embryos.

In addition, the embryos’ complete library of DNA would be decoded and analyzed to reveal genetic predispositions, both for disease and personal traits. The man and woman would get dossiers on the embryos that pass minimum tests for suitability. The couple would then choose one or two to implant.

The technology might also open the door to same-sex couples having children genetically related to both of them, though the additional twist of making eggs from men or sperm from women would be a bigger biological challenge.

As for decoding the complete DNA library of embryos, Dr. Louanne Hudgins, who studies prenatal genetic screening and diagnosis at Stanford, says some pregnant patients there say they’ve already had fertility clinics do that. They didn’t reveal why, Hudgins said. The president of the American College of Medical genetics and Genomics said, so far, no national medical association has endorsed decoding all the DNA of an embryo, which is called its genome.

Greely, meanwhile, calls his vision “easy PGD,” or prenatal genetic diagnosis.

Ordinary PGD has been done for decades. When a couple is known to be at risk for having a child with a specific genetic disorder, such as cystic fibrosis or sickle cell anemia, the woman undergoes a procedure to remove some eggs. After fertilization, some cells are plucked from the embryos and examined to identify those without the disease-causing abnormality.

That procedure looks for a specific problem in a few embryos, not entire genomes from dozens of them. If a couple wishes to select a “super baby,” says Dr. Richard Scott Jr., a founding partner of Reproductive Medicine Associates of New Jersey, “We tell them we can’t do it.”

Of course, with the artificial creation of many more human embryos with only one being selected for implantation, most will need to be destroyed.

Lori B. Andrews, a professor at the Chicago-Kent College of Law, concluded: “The idea of easy PGD should make us uneasy indeed.”

Nevertheless, others say it should be taken seriously.

“It’s certainly something we have to take seriously and think through now,” said Marcy Darnovsky, who writes on the politics of human biotechnology as executive director of the Center for Genetics and Society in Berkeley, California. “This is not just a technical or science question.”

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