CHICAGO (AP) — Baby-making is probably not on most families’ minds when young children get cancer. But at some pediatric centers, doctors bring it up soon after diagnosis because cancer or its treatment can cause infertility.

In children as young as infants, they’re trying a futuristic approach — removing and freezing ovaries and testes, with hopes that by time kids reach adulthood scientists will figure out how to make the tissue work.

It has worked in adults; more than 30 babies have been born to women who had ovarian tissue removed and frozen in adulthood. But no one knows yet if it will work in kids treated before puberty.

Patients at Lurie Children’s Hospital in Chicago and Children’s Hospital of Philadelphia are among kids involved in the research.