More medical schools were found to have disadvantaged female applicants in their entrance exams, in a survey taken after the discovery that a Tokyo medical university had manipulated test scores to curb female enrollment, education minister Masahiko Shibayama said Friday.

Shibayama told a news conference that there is a “strong suspicion” of undue bias against female applicants, and men who have failed the exams in the past.

Excluding Tokyo Medical University, none of the 81 schools covered by the ministry’s survey have admitted to rigging exam scores to discriminate against applicants by gender or age.

The Ministry of Education, Culture, Sports, Science and Technology conducted on-site probes at around 30 universities that had significant disparities in pass rates between female and male applicants in the last six years. In the probes, the ministry found evidence suggesting that examinees had been treated unfairly based on their gender or a record of past failures.

“It is problematic that university entrance exams that should be held fairly have been conducted in this way,” Shibayama said.

He withheld the names or number of universities suspected to have manipulated exam scores as it remains unknown whether there were reasonable grounds to support cases where the treatment of applicants differed.

The ministry plans to further investigate its suspicions and compile an interim report in October. It will also conduct on-site surveys at all universities with medical departments to release a final report by the end of the year.

Last month, the ministry’s preliminary survey results showed that men had passed entrance exams more frequently than women at 78 percent of medical schools polled after the scandal. The average ratio of successful male applicants to female stood at 1.18.

In August, Tokyo Medical University admitted it had maintained a practice of making deductions from entrance exam scores for more than 10 years to curb the enrollment of women as well as men who had failed the exam a number of times.

The rigging was aimed at keeping the proportion of women studying at the university at around 30 percent. The institution believed that would prevent a shortage of doctors at affiliated hospitals, on the grounds that female doctors tend to resign or take a long leave of absence after getting married or giving birth, according to an internal report and university sources.

The medical school also disliked accepting male applicants who had failed a number of times because they also tend to fail the national exam for medical practitioners, which would bring down the university’s ratio of successful applicants and hurt its reputation, according to the sources.