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For people who choose this type of treatment but want the option of having a biological child someday, there are a handful of options. Adults can freeze their eggs, e.g. But this typically includes stopping the testosterone treatment and allowing the menstrual cycle, which can take months, to return. Hormone-based medications are used to stimulate the ovaries to release multiple mature eggs, which are then collected in a surgical procedure involving vaginal probes. Babayev says the procedure can be particularly distressing for trans men. Also, taking a break from testosterone therapy for months can cause fatigue, mood swings, and sleep problems.

D. Ojeda, senior national organizer of the National Center for Transgender Equality in Washington DC, says many trans men would want to be able to start their own families without such setbacks.

Options are even more limited for teens who want to begin gender-confirming medical care before they reach puberty – meaning they cannot freeze their eggs because they have not started to ovulate. They can choose to have some or all of their ovaries removed and frozen, in which case the tissue can theoretically be re-implanted later – but very few trans men opt for this procedure because it raises estrogen levels in the body, says Kenny Rodriguez. Wallberg, a reproductive oncologist at the Karolinska Institute in Sweden, also saw Telfer present her work.

The alternative that Telfer and colleagues are working on involves removing the ovaries from the ovaries and maturing them outside the body in the lab. The team already had some success in doing this with eggs taken from the ovaries of women, but they didn’t know if people who had already started sex-confirming medical care would be able to mature eggs from their ovaries.

hard ovaries

Telfer’s first task was to find out what testosterone therapy does to the ovaries, a subject of disagreement among clinicians.

To get a clearer idea, Telfer collaborated with two gender validation clinics in the UK. Trans men who took testosterone and had surgery involving the removal of their ovaries were asked if they would like to donate to the research. In total, four people donated eight ovaries. The team compared the pieces of the ovaries to eight strips donated by women of the same age who had a cesarean section.

Trans men’s ovaries were really different – they had more collagen and less elastin, making the tissue harder. This stiffness can make it difficult for follicles to grow and release mature, ready-to-fertilize eggs.

more options [to start a family] we have trans people, that’s good.

D Ojeda, senior national organizer at the National Center for Transgender Equality in Washington DC

Telfer and colleagues also evaluated 4,526 follicles from parts of eight ovaries exposed to testosterone. About 94% of follicles were not growing, compared to 85% of ovarian fragments in women who did not receive testosterone.

The team then tried to mature eggs from the ovaries of trans men. Their method involves cutting the tissue surrounding each follicle and then stretching it onto a plate. This seems to trigger signaling pathways that allow follicles in the tissues to release mature eggs.

It worked—the researchers were able to mature a small number of eggs to a point where they were ready to be fertilized by sperm.

In theory, the team could use IVF techniques to create embryos with eggs and these embryos could be transferred to a partner’s or surrogate’s womb. To do this in the UK, the team must obtain a license from the Human Fertilization and Embryology Authority. No such license is required in the USA.

Ojeda says the technique will appeal to some trans men: “More options [to start a family] We have it as trans people, that’s good.”

Yet Telfer and his colleagues have not gone that far yet. The first eggs the team matured in the lab didn’t look completely normal. When eggs mature, they typically go through a special type of cell division that halves their chromosome number and prepares them for fertilization. The unused chromosomes separate into a small cell called the polar body. The polar bodies of the eggs matured in the lab looked unusually large.

A large pole body is likely to be completely harmless. But the team changes the content of the liquid in which the eggs mature, just in case. More recent attempts have resulted in more typical-looking eggs, Telfer cells. The team has matured around 10 eggs so far, but the project continues. “I want our culture system to be more robust before we attempt fertilization,” Telfer says.

He wants to try the process in sheep before trying it on humans. These experiments are scheduled for this year. If successful, Babayev predicts the technique will spread among clinics. Most fertility treatments skip clinical trials before they are widely offered by clinics.

“Obviously such issues will need to be resolved, but if he is successful, I don’t think it will take long for others to implement it very, very quickly,” Babayev says. But more evidence awaits to be convinced that the technique will work clinically. “I’m going to have to see a baby,” she says.

If it can be used to help transgender men have healthy babies, Rodriguez-Wallberg says the technique could be useful in many other situations as well. Children facing cancer treatments that can damage their ovaries may have parts frozen first, giving them a way to have their own biological child when they grow up.

Kutluk Oktay, a reproductive endocrinologist and fertility preservation specialist at Yale School of Medicine, says the method could also help others in their struggle to conceive. Ovarian freezing can be an alternative to egg freezing: taking a single biopsy from an ovary may be preferable to the many steps involved in egg collection.

While egg collection tends to result in about 10 eggs at a time, a small piece of ovary can be used to produce 100 eggs. “A small biopsy of the ovaries… may be enough for many babies,” Oktay says. “If we can figure out how to do this efficiently, it can be widely used.”