Sperm and Eggs for everyone? Not yet, but when we succeed with mice, the clinic won’t be too far behind

The fundamental building blocks to fertility success include good quality eggs and sperm.

For patients afflicted with either very low ovarian reserve or azoospermia (no sperm), choices today are limited. Couples must consider donor eggs or donor sperm. Until recently, science hasn’t had much more to offer. Though we do not have anything new to offer clinically right now, the hope is that in a few years we will be able to “build” eggs and sperm from stem cells for every patient.

There has long been hope that we could mature sperm from stem cells in the laboratory. Indeed, there may already been some success with this in the lab, using mice (paper; popular press article here). Perhaps one day, we will be able to take stem cells from anywhere (a cheek swab, for example), and mature sperm from the isolated stem cells. To be clear: we aren’t there yet. But the potential for success we have seen in mice portends well for the clinic.

Until recently, we had much less hope for eggs. This is based on the enduring dogma that women are born with all the eggs they will ever have. If true, that would mean there are no stem cells for eggs in adults, and the goal of maturing eggs would be very elusive indeed.

But, along with some other leading researchers, Dr Jon Tilley has questioned this dogma for years. He has been actively looking for the stem cells that build eggs. While his team has researched bone marrow and other locations for stem cells that could generate eggs, it is in his most recent paper in Nature Medicine , he believes he has found those stem cells in ovaries themselves.

It is an extraordinary leap forward, for he and his team have found the stem cells that can go on to become immature eggs. The hope is that, with a little more work, we will be able to identify the stem cells in all women, generate mature eggs, and provide hope for fertility where none may have previously existed. The implications are profound: if we can help to generate an indefinite number of stems cells that lead to eggs, then, we can generate an indefinite number of eggs. Menopause, for one, would become optional, as would age-related subertility.

We are not yet ready to offer such services to patients. But the news from the lab is promising indeed. When it comes to science, estimating timelines is difficult. I would think we are still some years away. Nonetheless, this is very exciting basic research, and while the focus of this site is for clinical practice, I thought that this paper, in particular, was worth mentioning.

For more, a good article was written by Stephen Adams for the Telegraph newspaper. 

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