>> reporter: mary lou henner starred as elaine single mom who drove a cab on the hit show "taxi." >> was happening in america. in the '70s, women were saying "marriage isn't what i thought it would be. i don't want to be somebody's wife." >> reporter: tv reflecting a new found america. between 1970 and 1980 the number of working women aged 25-34 increased nearly 50%. so what would mary and rhoda think of the women on tv today? >> they would be envious. if you remember women couldn't get pregnant at work until 1978. >> reporter: the year women could no longer lose their jobs just for getting pregnant. but it would take another 15 years before the family medical leave act was passed. allowing 12 weeks of unpaid leave to care for a newborn or family member. and while salaries have increased since the 1970s, women still make, on average just 78 cents for every dollar a man earns. a political issue then. a political issue now. >> i don't think i am letting you in on a secret when i say -- too many women still earn less than men on the job. >> reporter: as hillary clinton chases the nation