Gender confirmation surgeries can improve the quality of life of transgender people, according to new research.

Researchers in Germany followed 156 patients who underwent male-to-female transition surgery at the University Hospital Essen. The patients’ well-being was assessed using a variety of questionnaires, including one developed by the researchers specifically for transgender people. After surgery, 75 percent were more strongly satisfied with their lives, and 67 percent were satisfied with their outer appearance as a woman. The findings, which were presented last weekend at the 33rd European Association of Urology conference in Denmark, suggests that gender confirmation surgery can be valuable for certain patients.

Transgender people can feel emotional distress, anxiety, and depression when the gender they identify with doesn’t match the gender on their birth certificates — a condition called gender dysphoria. Treatments include counseling, hormone therapy, as well as gender confirmation surgery in some cases. Understanding how valuable this surgery is for patients is key to making the procedure more acceptable, as well as to convince governments to cover the costs. This latest study suggests that the majority of transgender people who undergo the surgery benefit from it.

75 percent were more strongly satisfied with their lives

Researchers at the University Hospital Essen identified over 600 patients who, between 1995 and 2015, transitioned from male to female through surgery at the hospital. Of those, only 156 were included in the study. (Many couldn’t be contacted, others didn’t respond, and a few said they weren’t interested in participating.) These patients were given a variety of questionnaires to assess their quality of life, including a one-question survey that asked them to rate their overall quality of life at different points of time, like when they came out as a transgender person, when they started hormone therapy, and after they underwent surgery.

The researchers also used a questionnaire specifically designed for transgender people, called the Essen Transgender Quality of Life Inventory. This survey has questions tailored to transgender people that traditional quality of life surveys don’t have. For example, the Essen questionnaire asks patients to rate how often they suffer “from being born in the wrong body,” says Jochen Hess, deputy head of the urology department at the University Hospital Essen, who helped create the survey. Other questions deal with harassment, stigmatization, and difficulty dealing with public authorities.

Of the respondents, 75 percent felt a strong enhancement of general life satisfaction after the gender confirmation surgery, and 67 percent were satisfied with their outer appearance as a woman. More than 80 percent also perceived themselves as women, while 16 percent saw themselves as “rather female.” And 76.2 percent said they could have orgasms. Hess says that he and his colleagues expected the surgery to have positive results. But “it’s one thing what you feel and one thing what it’s reality,” he tells The Verge. “We’re quite pleased that our feeling and the reality are matching quite well.”

The study has some limitations. It includes few participants, and all of them had surgery in the same hospital. Plus, even though the researchers found an improvement in their quality of life, the transgender people in the study had a lower quality of life compared to a cisgender control group. Still, this information is important to convince the medical community and government agencies that gender confirmation surgery can have a big impact on transgender people who have higher rates of stress and mental illness than cisgender people. In 2016, for example, the US Department of Veterans Affairs denied a rule change to start covering the costs of gender confirmation surgery for transgender veterans.

As for the Essen transgender-specific questionnaire, Hess says he’s hoping that it’ll soon be translated into Italian and English so that it can be used to more accurately assess the quality of life in transgender people outside of Germany. “Maybe we have to possibility to spread this in other countries,” he says.