The study, from the University of Auckland, compared census data from 1971 - before equal opportunities legislation was introduced - with data from 2001. It focussed on healthcare workers aged 18-44, since this age group would best reflect any changes resulting from such legislation.
Researchers found that out of the main 23 healthcare professions in 1971, men dominated 10 of them and women dominated the remaining 13. By 2001 however, none of the fields previously dominated by men remained so - eight had become balanced between both sexes, and two had become dominated by women. However, of the female-dominated professions in 1971, women continued to lead in 2001, outnumbering men heavily in most of them.
The researchers argue that given the high quality of data, plus similar trends shown in studies from other developed countries, these results may be common elsewhere.