My Mother-in-Law Got My Daughter to Stop Biting Her Nails. I’m Upset About Her Methods.

Care and Feeding is Slate’s parenting advice column. Have a question for Care and Feeding? Submit it here .

Dear Care and Feeding,

My 5-year-old daughter, “Wren,” has been a nail-biter for the past six months. Nothing my husband and I tried could break her of the habit. Then miraculously, she stopped. When I mentioned my relief to my mother-in-law, she took credit for it. Then she told me her “solution.”

She told Wren that her hair would fall out if she kept biting her nails! I’m not sure how to feel about this. On the one hand, I’m pissed my mother-in-law would lie to my daughter. On the other hand, it worked. Do I need to tell Wren the truth, or can my husband and I (at least for the time being) keep up the ruse?

—Something to Chew On

Dear Something to Chew On,

Look, we l