The jobs that have become more female are generally professional or managerial ones, the study found. Some examples of high-paying, high-status jobs done mostly by men in 2000 that had an increased share of women by 2014: supervisors of scientists, which had 19 percent more women, podiatrists with 8 percent more and chief executives with 5 percent more.
Jobs that were mostly female in 2000 and have become more masculine are lower-status jobs. The share of women who work in stores selling products and answering customer questions fell 10 percent; the share for crossing guards and counter clerks each fell 7 percent, and for textile workers it fell 5 percent.
Men are much less likely to have moved into the higher-status professions that are majority women, like nursing and high school teaching (they became more male by about 2 percent between 2000 and 2014.) The share of women grew slightly in two female-dominated professions, social worker and librarian.
Race, ethnicity and gender have always contributed to who does what work. Women have typically entered occupations when men find better ones, and immigrants have filled the ones women left behind. In the 1800s, according to previous research by Ms. Roos and Barbara Reskin of the University of Washington, Irish men replaced native-born white women in textile mills. The women moved to middle-class jobs like teaching — which native-born white men were leaving.
The current patterns reflect widening inequality as a whole, said Leslie McCall, associate director of the Stone Center on Socioeconomic Inequality at CUNY, who was not involved in the new research but said it was consistent with past findings. She said it shows that policy makers who want to improve jobs should focus not on gender or race, but on general working conditions at the bottom of the income ladder.
"People are focusing too much on the white, male working class," she said, "but if you look at the working class more broadly, the issues are quite similar across all groups: wages, economic security, employment support, training."
The Rutgers researchers used census data to track 448 occupations. Occupations were considered male or female if they had more than 60 percent of one sex in 2000, and they were considered to have masculinized or feminized if the percentage of men or women changed by at least 4 percent by 2014. This happened in 27 percent of occupations.
Health care showed some of the most striking changes: Every health care job except one is more female than in 2000. (The exception is radiation therapists: from 72 percent female to 65 percent.) The share of female dentists, optometrists and veterinarians each increased by more than 10 percent. The majority of doctors are still men, but women have become the majority in some health care specialties, including pharmacists and veterinarians.
Men's movement into low-skilled women's jobs since 2000 is partly a result of the hollowing out of middle-skill jobs in fields like clerical and manufacturing work, which was described by the economist David Autor. Women were hit harder — female employment in those jobs fell 16 percent from 1979 to 2007, compared with 7 percent for men. But women almost uniformly moved into high-skill jobs, while men were more likely to move into low-skill, low-paying jobs.
Other research has found that men resist so-called pink-collar work, and those who end up in the lowest-status of those jobs, like nurses' aides who bathe patients and change bedding, are already disadvantaged in the labor market because of race and class.
Sociologists have described the phenomenon as a trap door; these men drop into less desirable jobs. At all levels of work, it seems, white Americans have more choices.