A few minutes ago I got the news that my daughter's mother-in-law has stage 4 cancer. I was still staring at the computer screen, trying to digest the information, when a friend forwarded me a report on a Canadian study with this headline: "Female Caregivers Face a Heavier Toll."

Yes, we do. My mother died almost exactly 15 years ago, four months after my father died. Both had Alzheimer's disease. Both were in a nursing home about five minutes from my house. I visited them at least several times a week, sometimes daily.

"We're so glad we had a daughter," my mother used to tell me. "It's only the daughters who visit." She wasn't entirely right: Several sons joined the many women who visited regularly. Though the study said six in ten caregivers are women, in my parents' nursing home the number must have been closer to eight in ten.

Warning: If you are a woman with a spouse, parents, or parents-in-law, you are likely to spend a number of years as a caregiver.

"In terms of society's norms, the responsibility to care for parents tends to fall on the women," said Marina Bastawrous, the author of the study, who discovered that 40 percent of female caregivers experience high-level stress. Women, she noted, are more likely than men to quit their jobs in order to care for their parents. When my parents started needing more care than I could handle along with my demanding job, I cut my hours back to 30 a week. Eventually I quit altogether. More information on the toll that caregiving takes is available from the Family Caregiver Alliance.

Sadly, according to the Canadian study, despite—or perhaps because of—all their hard work, "adult daughters suffer more than adult sons from poor relationships with ailing and aging parents who need their care." If we care for our parents because we want to be thanked, or because we want to be closer to them, or because we have a romantic vision of saintly elders, we are likely to be disappointed. A bookstore assistant, noticing the book I was buying on caregiving, said to me, "God bless you, dear—I remember those days. Nothing you do is ever right."

To be sure, nothing is ever enough. Nothing will restore our parents' youth. Nothing will keep them from eventually dying. Nothing will keep us from our own certain decline. And yet we continue to care and to hope. That is what love does. Not sentimental, stress-free, feel-good love, but tough love that does what needs doing.

My daughter's mother-in-law has no daughters, but she has an excellent husband and three good sons who love her very much and are already doing what they can for her. She also has three fine daughters-in-law, one of whom has been taking her to her doctors' appointments all week. Chemo begins Monday. We are all praying for their strength and her healing. Please pray with us.