Editor’s Note: Bill Gates Sr. is a lawyer, philanthropist, civic activist, husband, father and grandfather, not necessarily in that order. He currently serves as co-chair of the Bill & Melinda Gates Foundation. He is the author of the new book Showing Up for Life: Thoughts on the Gifts of a Lifetime.

Over my lifetime, I’ve know some very strong women. I’ve also seen how women’s lives can shrink when they’re denied opportunity because of others people’s narrow expectations.

I grew up during the Depression years in the 1930s. My mother was an open-minded person who didn’t have a lot of fixed ideas about what my sister, Merridy, and I should do growing up. But Dad, who was somewhat insecure about his lack of formal education, found comfort in living by a number of inviolable maxims, such as, “If you expect to make something of yourself, you’ve got to work hard.” But some of his other axioms allowed me to see, early on, the sometimes-unintended harm that can be caused by close-minded thinking. Another of his axioms was “girls don’t go to college.” That belief had a limiting influence on Merridy’s life.

When we were growing up, I often felt uncomfortable that there were different rules for Merridy because she was a girl than there were for me.  One example is that she never learned how to drive a car. I, on the other hand, was permitted to get my driver’s license the minute I turned 16.

By that time, Merridy, who was seven years older than I, was married. She had a job and was earning her own money. For my 16th birthday, she spent 85 dollars – which was a significant sum then – to buy me a birthday present: a 1930 Model A Ford roadster with a rumble seat. Merridy’s generosity – when she had been denied the opportunity to drive herself – is something I’ve never forgotten.

It’s hard to know how events like this shape your perspective. I’ve married two strong women and raised two strong daughters. My first wife, Mary, mother of our three children, was someone who believed in “tall thinking” and in creating the change you’d like to see happen in the world.

We met and started dating in college. After she graduated, Mary became a teacher and then started a lifelong career in public service, tutoring children who were having problems at school, and going into homes as a United Way volunteer to help single parents with kids get by after a mother or father had died or left home. Over time she assumed leadership positions with United Way of America and United Way International and she became a powerful voice for children, lobbying officials in both Washingtons on behalf of Children’s Hospital. Known for her optimism and her ability to see the bigger picture, Mary became a member of the first cohort of women sought for corporate board positions.

Rather than see herself as a token woman and act accordingly, she viewed those corporate appointments as opportunities to create the changes she wanted to see happen in the world. She worked hard, proved that she was diligent and smart and earned the respect of her colleagues.

Another facet of Mary’s persona that shone through all her spheres of influence was her enthusiasm for life. Her well-known sense of fun was one reason our friend Meg Greenfield, a Seattle native and editor of The Washington Post, called us up one Fourth of July weekend.