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

Education minister Masahiko Shibayama told a press conference that there is a "strong suspicion" of an undue bias against female applicants and men who failed the exams in the past.

(The entrance of Tokyo Medical University)

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 which had significant disparities in pass rates between female and male applicants in the last six years, and found evidence suggesting that examinees were treated unfairly without prior notice based on their gender or the 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 the different treatment.

The ministry plans to further look into the 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.

(Education minister Masahiko Shibayama)

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

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

The rigging was aimed at keeping the proportion of women studying at the university at around 30 percent to prevent a shortage of doctors at affiliated hospitals, on the grounds that female doctors tend to resign or take long leaves 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.