Sixteen years ago something unexpected happened: I became the mother of a daughter. Our assumptions about the unlikelihood of this had a weird logic, my husband the eldest in a family of six boys, our first two children sons. Third time around I looked exactly the same (enormous), and my habitual nausea had given way to my habitual urge to eat anything with salt or sugar and most of what lay in between. Which explains why, when our doctor said, "A little girl," I upended that newborn right there in the birthing bed and double-checked.

Having a daughter can be a complex matter for a woman. Despite those who burble about someone to shop and chat with, the truth is that in their search for self, girls challenge their mothers in a way that boys rarely do. The ruling principle of burgeoning female identity seems to be a variation on Descartes: I am not my mom, therefore I am. Prudence Quindlen's revenge, my father once called our youngest child, figuring she would give me the agita that I had given my own gentle mother. Certainly that has sometimes been the case. But Maria has done something for me that I never anticipated. She made me want to be a better woman.

If I were pressed for one word to describe my only daughter, it would be courageous. Swimming underwater at 2, jumping off the diving board at 3, barreling off a 40-foot cliff into the Caribbean in Negril at 5 as drunken college students cheered--that's my wild, brave girl. The orthopedic surgeon put Maria in a hot-pink cast after repairing her knee because she was convinced her 14-year-old patient was incapable of being cautious. (Smart doctor--day two and the patient was up on the roof, crutches wound with glittery tinsel, celebrating the new year with a clutch of friends.) After all, she'd torn her meniscus in the first place chasing a loose ball on the basketball court so aggressively that she hit the gym wall with a sound like a sonic boom.

She is the girl who effortlessly emceed the school Battle of the Bands and sobbed unabashedly onstage as the terrified wife in "A View From the Bridge." At her summer camp the counselors were allowed to create ad hoc daily activities, to share skills and talents; some years ago one of them offered a session titled "Getting to Know Maria," and more than two dozen campers signed up. She makes me believe in evolution. She's an authentic human being in a way I was not at 16, less good girl, more real person. She and her wonderful group of friends--yeah, Phat Rebels, you know who you are--deal with one another more honestly and more productively than my friends and I did at the same age. It took me decades to learn what these girls seem to understand intuitively: not to confuse disagreement and rupture, conflict and loss of love.

They've hit the ground running because of the changes in the lives of women. The culture grants them opportunities that were once male-only, but it still gives to girls with one hand and takes back with the other. I wonder sometimes about the tradeoffs: aprons for eating disorders, strictures for stress, limits for deceptively limitless choices. Still, while my mother's generation couldn't even imagine certain freedoms and my generation grew up fighting for them, liberation is the birthright of this group of young women. You can feel it in their strength.

Each wave of feminism has believed in something called the New Woman. The woman who could vote, who could work, who could be truly free. I am the mother of the New Woman. She doesn't waste a lot of time tailoring the cut of her character to suit the demands of a world that has always had mediocre taste. She never milks her gender, and she is not cowed by guys. She has taught me to dare more and conform less, to cut down on my hypocrisy because she shames me by seeing right through it. Being her mother is like playing basketball with a crack player (and she is that); she raises the level of the game of life just by showing up.

Sixteen years ago I got a second chance at my own life, like reincarnation without the death part. As Martina McBride sings about her own daughter, "The truth is plain to see: she was sent to rescue me." I read a book called "Mother Daughter Revolution" when Maria was a toddler and underlined this sentence: "Suddenly, through birthing a daughter, a woman finds herself face to face not only with an infant, a little girl, a woman-to-be, but also with her own unresolved conflicts from the past and her hopes and dreams for the future."

My hope and my dream for the future of women comes trudging up the stairs every afternoon, her hair bundled into a bun. Last year she gave almost a foot of it away to make a wig for a kid going through chemo, but she mourned her lost length tearfully for a week afterward. Don't get me wrong: she's no saint. But she is strong and smart and funny, everything I've ever treasured. Oh, if I could grow up to be Maria, to be the kind of person who could jump off that cliff without thinking twice or looking down. For decades my role model was my mother. Now it's my daughter. I'm just the woman who was lucky enough to come between the two.