This morning I chose to exercise rather than sleep later. I chose to eat cereal for breakfast rather than eggs. These are pretty easy choices, but some choices are a little harder.

For instance, when I had my first daughter, I chose to leave my steady job on Capitol Hill in favor of less certain, but more flexible, independent work I could do from home. One friend of mine decided to stay home full-time as a mother after her first child was born, giving up her entire salary for her family. But, with the bad economy dragging on, she has gone back to work part-time. Other friends chose to keep full-time jobs and balance their work and family time in other ways. None of these choices came without tradeoffs, and no one decision will work for everyone.

But while choices are a sign of freedom, too many people today don’t understand that with freedom come costs. There’s an attitude in popular culture – and especially among most feminists on the left – that it’s unfair to expect people to accept responsibility for their choices. Especially women – that’s so passé.

The so-called wage gap is the prime example. The reality is that discrimination is not a significant reason why women earn less than men on average. Yes, there are bad employers out there who still might discriminate against women. But in the aggregate women are outperforming men in terms of college-graduation rates, advanced degrees, purchasing power, and even higher earnings in some areas.

So what, then, explains the difference in pay between men and women? It comes down to choices. Even Warren Farrell, who has served three times on the board of directors of the National Organization for Women, explains in his book Why Men Earn More that choices largely account for the differences in earnings between men and women.

While more women than men are earning bachelor’s degrees, for instance, women are choosing to major in less competitive disciplines. A study produced by the Federal Reserve Bank of New York in 2009 considered what factors male and female students use to choose a major. While it’s hard to pinpoint just one reason for their decision, the author found that men and women alike made their choice based on potential outcomes. The difference is that female students on average cared more about “non-pecuniary” issues like parental approval and enjoyment of future work, while male students were concerned with just the opposite – “pecuniary” issues such as likelihood of finding a job, earning potential, and social status of future jobs.

Similarly, more than three-quarters of American teachers are women. So while nearly half the nation’s workforce is composed of women, many are choosing fields that are less lucrative than the ones many men are choosing.

Some of these differences may be explained by biology and may reflect innate aptitudes and preferences, while others may be a function of society and culture. Of course, nature and nurture can be difficult to separate – individuals with a natural talent may find they are driven by their environment toward disciplines that make use of that talent.

A recent Harvard economics study found that while women have made tremendous strides in terms of gaining access to careers in business – females now make up 40 percent of MBA classes nationwide – some of these careers are more challenging for women (and men) who want to have families.

In fact, the study found that at the time of their 15th college reunion, fewer than half of the female MBAs reported having children and working, compared to two-thirds of the female MDs. Top jobs in finance still require longer hours – for both sexes – than even other highly skilled professions like medicine and law. The choices women make have costs – salary must be weighed against time spent with family, time for other personal activities, etc. But the costs are the result of a woman’s free choice, not an injustice imposed on her by society.

Many traditional feminists, however, view these decisions as a sign that society – and especially the workplace – remains hostile toward women. They don’t believe that women should have to make the choice between, say, investment banking and law – or between investment banking and motherhood.

I recently appeared on a television panel with the president of a leading national feminist organization. I shared with her that when I worked on the Hill I accepted a lower salary than I had originally asked for because my husband and I wanted to start a family. I valued my time as much as, if not more than, the money, and I wanted to be in a strong position to negotiate flexible working hours when the time was right. My co-panelist couldn’t understand this. She said, “But you shouldn’t have to choose.”

Really? Why should my employer be forced to pay me a high salary and give me flexible working hours? Why should someone else take responsibility for my choices? Perhaps a higher salary with flexible hours is something I might earn if I do a good enough job; but the employer still needs someone to get the job done.

What’s more, men make similar decisions all the time. Some men, like some women, choose to be on a partner track at a big law firm, where they are expected to work demanding hours and have little time with their families. Other men with the same degrees choose to serve as counsel for a government agency or a smaller firm, where they make less money but also spend less time in the office.

It’s hard to know what makes women more likely than men to leave the workplace in order to care for young children. Is it societal pressure or perhaps just biology? It doesn’t matter as long as women – and men – are able to make the decisions that reflect their needs and wants, and those of their families.

Choices are difficult. But after all, it’s the ability to choose that makes us human.

– Sabrina L. Schaeffer is a senior fellow with the Independent Women’s Forum and managing partner of Evolving Strategies.