Women hope science will successfully put fertility in deep freeze.

Byline: Judith Graham

CHICAGO _ Christina Jones wants to have it all _ a career, a husband, kids _ but she's 34 and single. So Jones recently had medical specialists extract eggs from her ovaries and freeze them in liquid nitrogen.

Jones calls this "fertility insurance," a way of keeping her future reproductive options open as she gets older. And she's betting, as the founder of a new company marketing egg-freezing services, that many women will want to follow in her path.

But scientists have significant concerns about promoting what they say is an unproven and even risky technology to healthy women, the primary target for Jones' Boston company, Extend Fertility.

Their caution comes as fertility programs across the country are gearing up to start experimental egg-freezing.

Many of these new programs are for women with cancer, because treatment can leave women infertile. But other programs plan to tap a potentially huge and lucrative new market: women who have no foreseeable fertility problems.

Because infertility is a largely unregulated field, there is nothing to stop them.

Scientists warn that freezing exposes eggs _ exquisitely sensitive cells _ to significant stress and has not been established as safe yet for babies born through these procedures.

Fewer than 100 births have been reported from frozen eggs. Most of these children are quite young, and long-term studies of their health have not been done.

"Any patient who comes to us, we make it very clear this is very new technology and we cannot attest to its safety," said Dr. Kevin Winslow,…