Doctors use tissue slides like this one of the ovary's outer cortex to confirm a woman's ovarian reserve. It's also the the ovary tissue that's removed in an ovarian transplant. Courtesy of the Infertility Center of St. Louis hide caption

toggle caption Courtesy of the Infertility Center of St. Louis
Chance To Pause Biological Clock With Ovarian Transplant Stirs Debate
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Human embryos under a microscope at an IVF clinic in La Jolla, Calif. Sandy Huffaker/Getty Images hide caption

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Freezing Eggs To Make Babies Later Moves Toward Mainstream
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