I am trying to find statistics showing the ratio of males to females in the nurse and physician professions between 1970-2010.
Try the Bureau of Labor Statistics site to find information on men/women employment ratio in health professions. More precisely, their demographics page: http://www.bls.gov/cps/demographics.htm. Click on the link for the "Women" section. The “Highlights of Women’s Earnings” reports may be helpful, but the earliest report is from 1998. In the table titled “Median usual weekly earnings of full-time wage and salary workers by detailed occupation and sex” you will find the employment numbers by sex.
You may want to look at the National Center for Health Workforce Analysis site for some information related to your question http://bhpr.hrsa.gov/healthworkforce/.