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There are a number of options for people who want to have biological children, but choose not to. Adults can freeze their eggs. This usually involves stopping testosterone treatment and allowing a menstrual cycle to return, which can take months. A surgical procedure involves vaginal probes to collect mature eggs that have been stimulated with hormones. Babayev says the procedure can be distressing for trans men. testosterone therapy can be paused for months, which can cause fatigue, mood changes, and sleep problems.

D. Ojeda is a senior national organizer at the National Center for Transgender Equality.

Young people who want to start gender-affirming medical care before they reach puberty can't freeze their eggs because they won't have started ovulating. Kenny Rodriguez-Wallberg says that most trans men wouldn't choose to have their ovaries removed and frozen because it would increase estrogen levels in the body.

Telfer and her colleagues are working on an alternative that involves taking eggs from the ovary and maturing them outside the body in a lab. The team had success with taking eggs from women's ovaries, but they didn't know if they would be able to mature eggs from people who had already begun gender-affirming medical care.

Stiff ovaries

Telfer's first task was to find out what testosterone therapy does to the female reproductive system.

Telfer collaborated with two gender affirming clinics in the UK to get a clearer idea. The men who were taking testosterone and had their ovaries removed were asked if they wanted to donate their organs for research. Four people donated ovarian tissue. The team compared the pieces of the ovary with the ones donated by women.

The tissue in the ovaries of trans men was more rigid because they had less elastin and more collagen. It might be difficult for follicles to grow and release mature, ready-to-fertilize eggs.

The more options [to start a family] we have as trans people, the better.

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

Telfer and her colleagues looked at 4,526 follicles from the pieces of the testosterone-exposed ovaries. Around 85% of pieces of ovary from women who had not taken testosterone were not growing.

The team tried to mature eggs from trans men. Their method involves stretching the tissue out in a dish. The signaling pathways that allow mature eggs to be released seem to have been triggered by this.

The researchers were able to mature a small number of eggs to a point where they are ready to be fertilized by sperm.

In theory, the team could transfer the embryos from the eggs to the uterus of a partner or surrogate. The team needs a license from the Human Fertilisation and Embryology Authority to do this in the UK. No such license is required in the US.

Ojeda says the technique will appeal to some trans men.

Telfer and her colleagues have yet to go this far. The first eggs that the team matured in the lab were not normal. Eggs mature when they undergo a special type of cell division that halves the number of chromosomes. A small cell called a polar body is where the chromosomes are separated. The polar bodies of the eggs were large.

A large body of water is not likely to be harmful. The team is tweaking the fluid in which the eggs are matured just in case. More recent attempts resulted in cells Telfer. Telfer wants the culture system to be more robust before attempting fertilization.

She wants to try the procedure on sheep before she tries it on people. The experiments will take place later this year. Babayev predicts that the technique will take off among clinics if they succeed. Most fertility treatments do not go through clinical trials.

It will take a long time for others to implement it if she is successful. He would have to see a baby to be sure the technique will work.

Rodriguez-Wallberg says that the technique could be useful in a lot of other circumstances. Children facing cancer treatments that might damage their ovaries could have parts of them frozen first, offering them a way to have their own biological children when they are older.

Kutluk Oktay is a reproductive endocrinologist and fertility preservation specialist at Yale School of Medicine. Ovarian freezing could be an alternative to egg freezing if you want to avoid the many steps involved in egg retrieval.

And while egg retrieval tends to result in around 10 eggs each time, a tiny piece of ovary could be used to produce 100 eggs. “A little biopsy from the ovaries … might be enough for a lot of babies,” says Oktay. “If we can figure out how to efficiently do this, it could be widely used.”