General practice is a popular choice for female doctors
The rising number of female doctors is "bad for medicine", and universities should recruit more men, a GP warns.
Writing in the British Medical Journal, Dr Brian McKinstry said female doctors were more likely to work part-time, leading to staffing problems.
Women, who now outnumber men in medical schools, were also less likely to take part in training or research, he said.
But opponents said the best candidates should be chosen regardless of gender and flexible working policies improved.
Professor Jane Dacre, vice dean of biomedical sciences at University College London, said rather than worrying about having too many female doctors, there should be more focus on ensuring equal opportunities for medics throughout their careers.
"When I was at medical school, there was a quota and they were only allowed 30% women.
"There is quite a developing evidence base that female doctors are not inferior to male doctors, but in fact are doing better in terms of getting into medical school and in their exams."
But she said women doctors were still under-represented in some specialities, such as surgery, and at senior levels in the profession.
The best candidates needed to be chosen for medical school whatever their sex but flexible hours, on-site child care and part-time training options were needed to ensure women doctors had equal opportunities in their career, she said.
Women now outnumber men in most UK medical schools by three to two.
This has reversed many years of male dominance in medicine and unfair discrimination against women, said Dr McKinstry, who is also a researcher at the University of Edinburgh.
But the recent large rise in female medical graduates was worrying, particularly in more "family friendly" areas of medicine such as general practice, he added.
Many older full-time male GPs are shortly due to retire leaving behind a workforce of younger women, many of whom work part-time.
"I'm not meaning to be critical - women have a difficult time of it because they are left with the bulk of childcare.
"The main thing we need is a revolution in the attitude of society towards childcare and who has the responsibility for childcare.
"But I think medical school numbers should reflect society generally and we need a more even split between men and women."
In Scotland where he works, figures show that women GPs contribute about 60% of the activity of their male counterparts in training, teaching, research and committee work, he said.
A separate piece in the BMJ pointed out costs associated with poor performance, litigation, re-education, and rehabilitation were consistently higher for male doctors.
Dr Steve Field, chair of the Royal College of GPs, said he welcomed more women in the profession.
But he added that there were concerns over the fact that girls tended to do better in the interview process for medical school at age 18.
"I'm concerned about how we select into medical school as it seems to be more difficult for boys post A-level.
"I'm all for graduate entry, people who have already done a degree, as they come from more diverse backgrounds, they are more mature, and you also get more men."