DALLAS — There are many theories about why more women are filing into the veterinary profession's ranks faster than men, but a new study indicates the reason may be more simple than most realize.

Most men simply choose other career paths when women rank as the majority.

And it's a trend that will likely persist as the numbers of women entering the veterinary profession continue to climb, says Anne Lincoln, PhD, author of "The Shifting Supply of Men and Women to Occupations: Feminization in Veterinary Education." Lincoln, an assistant professor of sociology at Southern Methodist University, published the study in the July 2010 issue of Social Forces.

Veterinary medicine was 98 percent male in 1960, compared to 50.9 percent female today. Enrollment record-keeping in veterinary schools only goes back to 1976—a time in which men's applications and then enrollment began to decrease.

According to Lincoln, the number of men applying to U.S. veterinary colleges decreased by more than half from 1976 to 1995. During the same period, the number of women applicants nearly doubled. Veterinary schools now enroll 70 to 80 percent female students, and the American Veterinary Medical Association (AVMA) reported that women members outnumbered men for the first time in 2009.

Sex-integration at veterinary colleges may have been a factor in the influx of female applicants to veterinary colleges, but other evidence also goes to support Lincoln's theory.

"The results of the analysis indicate that for every 1 percent increase in women the veterinary college study body, about 1.7 fewer men will apply the subsequent year, Lincoln explains. "By comparison, each $1,000 increase in tuition reduces the number of male applicants by about 1.2."

Some are still quick to explain away the gender shift with things like improvements in animal restraints, flexible schedules for families, less gender discrimination, the role of women as nurturers as reasons why women are outnumbering men in veterinary colleges, but Lincoln says all those things are difficult to measure.

"The explanation of reduced barriers to admission for women has merit, although it fails to explain why other professions that have also eliminated that bias have not feminized or not at the same rate," Lincoln argues. "The results of this study demonstrate only one consistent difference between male and female application patterns—men's strong negative response to women's increasing enrollment."

Feminization of the veterinary profession has been fueled more by lower rates of college graduation among men and their aversion to female students than women being attracted to the field, Lincoln says. Similar trends have been noted in fields now dominated by women, like pharmacy, she adds. The trend now may also be extending to human medicine, with female applicants to American medical schools surpassing those of men for the first time in 2003. Wage stagnation over the last two decades has been linked as a factor in that case, with men more often choosing the more lucrative fields of business or law over medicine. Men also tend to revise their career plans based on decline in occupational prestige, employment security and promotional prospects, Lincoln adds.

"The devaluation of women's labor may stigmatize occupations with higher proportions of women in them such that jobs performed largely by women pay less than comparable jobs done by men, and men's wages within an occupation are lower the more heavily female-dominated it is," Lincoln writes.