When a trans person begins hormone therapy, many questions arise about the side effects of testosterone – both desired and undesired. Some relate to visible physical changes, while others concern longer-term effects. One of the most important is the impact of testosterone on fertility.
Can you have children after starting hormone therapy? Does testosterone cause infertility? Is it reversible? The answer isn’t entirely straightforward, but one important point should be clear from the beginning: testosterone influences reproductive function, but it does not always eliminate it permanently. That’s why at IM GENDER, this topic is approached with time and information, so that the best decisions can be made according to individual needs.
Side effects of testosterone injections on the body
Testosterone therapy affects many systems in the body, and the reproductive system is one of them. In trans men who retain a uterus and ovaries, menstruation typically stops after a few months, and ovulation is suppressed. This happens because testosterone inhibits the hormonal axis that regulates the menstrual cycle. The body no longer functions in the same way as before, and ovarian activity decreases.
If my period stops, does that mean I’m infertile?
In most trans men, testosterone causes menstruation to stop within the first few months of treatment. However, this does not always happen immediately. Some studies show that around 18% may still experience bleeding after three months, although this figure decreases significantly over time: after one year, persistent bleeding drops below 5%. Occasional spotting may also occur, which does not always equate to a full menstrual period.
In practice, many people interpret these changes as a loss of fertility. But that’s not entirely accurate. What happens is that reproductive function is paused, not necessarily cancelled. In fact, not having a period does not necessarily mean that ovulation has stopped. A 2024 study observed signs of recent ovulation in transmasculine individuals undergoing testosterone treatment with amenorrhea, meaning testosterone should not be considered a contraceptive method.
Is fertility lost forever?
This is one of the most common – and most important – questions. Currently, we know that in many cases fertility can recover if testosterone therapy is stopped in trans men. Over time, the body may reactivate the hormonal cycle, resume ovulation, and allow pregnancy.
However, it’s important to be honest: this does not happen in the same way for everyone. Some people regain ovarian function without difficulty, while others require assisted reproductive techniques. There are also cases where recovery is not complete. That’s why it is important to discuss fertility before starting testosterone hormone therapy.
Thinking about the future before starting testosterone therapy
Not everyone wants to have children. And not everyone wants them in the same way. But one thing is common: the moment when hormone therapy begins does not always coincide with the life stage when decisions about motherhood or fatherhood are made.
For this reason, before starting testosterone treatment, it is advisable to reflect and ask: do I want to keep the possibility of having biological children open in the future, even if it’s not a priority right now? If the answer is yes—or even if there is uncertainty—there are options available to preserve that possibility.
What options are available to preserve fertility?
The most common option is egg freezing. This involves stimulating the ovaries to retrieve oocytes and preserve them for future use. It is a well-known, safe, and increasingly accessible process.
It can be done before starting testosterone treatment – which is usually the simplest option from a medical standpoint – or afterward, by temporarily pausing treatment.
There is also the option of embryo freezing, which involves fertilizing the eggs before preservation, or in some cases, ovarian tissue preservation, although this is less common.
Not everyone needs to take this step, but it is important to know that this option exists.
The impact of surgery on fertility
While testosterone hormone therapy does not necessarily eliminate fertility, there are other procedures that are definitive.
With gender-affirming surgery, the possibility of carrying a pregnancy or using one’s own eggs may be lost. Examples include hysterectomy or oophorectomy, where the removal of the uterus or ovaries eliminates that option, as well as procedures such as phalloplasty or metoidioplasty.
These surgeries are part of the gender affirmation process for many trans men and may be necessary or desired. However, precisely because they are irreversible, it is important to reflect on fertility beforehand.
This is not about delaying the process, but about making decisions with full information.
A decision beyond biology
Fertility is not just a medical issue. It is also about how each person envisions their future, the kind of family they want to build, how they relate to their body, and the role they want genetics to play in that life project.
Some trans men wish to carry a pregnancy. Others prefer not to. Some choose assisted reproduction, others adoption, and others do not wish to have children.
All of these decisions are valid, but making them requires understanding the side effects of testosterone and considering all available options.
Deciding with information, not urgency
Testosterone can affect fertility, but not always permanently. The key is not to anticipate problems, but to understand the options before some of them are no longer available.
At IM GENDER, this guidance is part of the process. Because starting hormone therapy is not just a physical change. It also involves thinking about the future, and doing so calmly, with information, and with medical support.
If you have questions about the side effects of testosterone, gender-affirming surgery, or how these may affect your fertility, request a consultation with our medical team to get informed.
