At least 12 Swedish children have experienced unexpected physical changes after being mistakenly exposed to hormone gels and sprays in recent years, health officials told Euronows Health.
In one case, a 10-month-old Swedish girl developed an enlarged clitoris that resembles a small penis after lying on her father’s breasts, who was using testosterone gel.
In another case, the 10-year-old boy began raising his breasts after being exposed to his mother’s hormone treatment.
These cases have been reported by clinicians at Sargrenska University Hospital in Gothenburg, Sweden. He warns parents who use topical hormone medications to avoid direct contact after treatment is applied.
Hormonal medications contain sex hormones that our bodies begin to produce during puberty.
Topical treatments such as gels, creams, and sprays are prescribed to adults with hormone-related disorders, patients who have completed chemotherapy.
However, the risks of the Swedish doctor said children can use these treatments to absorb hormones through skin-skin contact, leading to medical complications such as reported in Gothenburg.
“Baby under 12 months old has very absorbable skin,” Dr. Giovanna Dahlgren, the chief physician in the pediatrics department at Sarlgrenska University Hospital, told Euroneuz Health.
She added that “the child has to spare” from the accidental exposure to a very powerful sex hormone.
There are other options for parents taking hormonal medications. Dahlgren recommends quarterly injections for patients taking testosterone, but patches and vaginal tablets could be alternatives to estrogen sprays.
She also said topical treatment can be applied to areas where parents are unlikely to come into contact with the child, such as the inside of their thighs and upper back, and recommends that the child be kept in a safe area out of reach of the child.
Despite the increasing number of cases, lack of awareness
According to Dahlgren, doctors at Sahlgrenska University Hospital began seeing cases of hormone exposure in children about eight or nine years ago.
Endocrinologists there raised the issue of local authorities, leading to new medical guidelines and updated the warning labels along with pharmaceutical companies that had given hormone treatments.
The growing popularity of online prescriptions may have contributed to an increase in cases, Dahlgren said.
In some European countries, including Sweden, Germany and France, telehealth platforms can legally prescribe hormones.
Since 2019, there have been 12 reports that “unintentional hormone exposure affects children,” according to Swedish medical products agency Läkemedelsverket. Two other cases have been reported to European drug regulators.
However, Dahlgren believes this is only a small part of the actual casualties.
“Our own cases are not expressed in these numbers,” she said.
The hospital is currently working with other local centres to map the range of these cases nationwide.
The problem is not isolated to Sweden
In 2024, a Welsh pediatric endocrinologist published a case series documenting children who developed early adolescent signs after exposure to hormone gels or sprays used by their parents.
The study included cases similar to those seen in Sweden, as well as cases of girls with breast development and mood fluctuations associated with maternal use of estrogen gel.
The researchers also highlighted the mental health effects of unexpected hormone exposure on both children and parents who often feel guilty.
Earlier this year, the Swedish trade magazine for healthcare professionals reported 41 reports of suspected secondary exposures in children and adults containing estrogen-containing drugs between 2018 and 2025, and 66 reports related to products containing testosterone between 2004 and 2025.
Follow-up care varies depending on the severity and duration of the exposure.
For example, a young girl with clitoris enlargement in Sweden recovered completely after the exposure was over.
But some young patients who have been exposed repeatedly over a long period of time and need to be followed up until adulthood, Dahlgren said.
For example, a 10-year-old boy with abnormal breast growth is waiting for breast reduction surgery, and bone growth can also be destroyed by accelerated bone age.
“We have to think about the long-term impact,” Dahlgren said.
These hormones are “steroids that act directly on DNA and alter protein expression throughout the body.”
She warns that long-term exposure to testosterone can increase the risk of clots, heart attacks, strokes and even cancer in adults. In children, the injury can be lifelong.
“That’s why I encourage people to know that these hormones are powerful,” Dahlgren said.