Society has always been obsessed with women's bodies. Even ancient Egyptian tomb paintings showed the wives and daughters of important men as svelte. But expectations of physical perfection are at an all-time high—oddly, as women have gotten more culturally liberated, we've also gotten crazier about our bodies. Americans, mostly women, spent more than $13 billion on plastic surgery in 2007; 10 million U.S. girls a year have eating disorders; and any magazine rack confirms our obsession with one scantily clad celebrity after another.

And these standards aren't for actresses alone. Look at any woman serving in Congress or working for a law firm or foundation. Everyone has her hair and nails done, her body in reasonable shape. (See my own routine at right.) It's wonderful progress that we now accept that powerful women can look great. But must they, every minute of the day? As a requirement for success, beauty becomes just another burden.

The marriage standard

In the 1960s women needed their husband's signatures to open credit cards; our grandmothers couldn't hold mortgages unless they married. Once they did, they got sex, families, and respectability. We have more options today, but we've also raised our expectations of marriage. It's not enough anymore to settle down. It's all about fireworks, coparenting, lifelong romance, and ecstatic sex. And some of those goals are at odds:

• We want to be fully involved in our children's care—without compromising time at work, with spouses, and for ourselves.

• We want men to love our independence and gas up the car.

• We want to achieve pay equity with men, but we prefer our husbands to earn more than we do. (Related: We want Martha Stewart's media empire and doilies but not her divorce.)

• And whether we're working as truck drivers or consultants, we want to be good homemakers, mothers, and wives.

True love is a gift. But expecting marriage to be perfect... that's just another Wonder Woman myth.

The motherhood standard

And then there are our sky-high expectations of ourselves as mothers. While pregnancy today is blessed by the light of adoration that glimmers off Renaissance Madonnas and tabloids constantly screen for "baby bumps," technology has created at least 15 additional ways to have a baby, none of which involves sex. It used to be enough for us to have kids and see them live through childhood. Now we time births to our career moves and reimagine pregnancy as a sexy sideshow.

I have a friend, a glamorous 42-year-old career woman, who couldn't carry a pregnancy. So she and her husband spent tens of thousands of dollars interviewing surrogacy agencies, surrogates, and doctors to extract her eggs. They made embryos, froze them, and implanted them in strangers' wombs. Nothing worked. Three years in, she's doing IVF again. "It's so hard," she told me. "I just want a baby."

Once, she would have adopted. Now we've set the standard that if you can become a biological mom—by spending exorbitantly and undergoing endless medical procedures—then you should. Is that liberating? To me, it feels like another way women have to be perfect or, in this case, perfectly fertile.

Next: The Homemaker Standard >>