At this point the women's movement in Ireland was still very new, but having spent time in America, Mary Robinson believed that everything was possible. When the Irish Senate Elections were held in 1969, the University traditionally returned six senators but Robinson was ready to challenge the system.

 "I posed the question why is it always elderly male professors and my colleagues said well you're right, why don't you stand. And I stood in 1969 and was elected very much against the odds - I mean being a Catholic, being female and being much younger than normal. It was the first time I understood that 3 disadvantages can turn to an advantage and you can win through. I then became involved in quite a controversial issue, because I promoted in early 1970 a bill to legalise the availability of contraceptives, and at the time that was extremely controversial. I received a lot of hate mail, a lot of public criticism, and I learned … a valuable lesson early in life and that is if you believe in something, keep your head down and pay the price of being unpopular in short term, but go ahead and stick to your principles."

Robinson was prepared to be unpopular in order to achieve what she believed in - to make it lawful for contraceptives to be available in Ireland. She married a Protestant lawyer, had three children and continued working as a lawyer. She gained a reputation in court for her work for women's causes and defence of human rights in Ireland.