Judged by another parent? Here's a theory on why it hurts so much

You use cloth diapers for your baby. Your friend uses disposables - and you think maybe she could try harder to be eco-friendly. Do you let the sentiment pass your lips? Probably not, if you can help it.

Because, as Judith Warner writes in Sunday's New York Times, nothing can deep-six a friendship like differences over parenting - especially in an era when there seems to be no general consensus on anything. Parents argue over every detail, from the best first food for infants to how to discipline a toddler. So with every minute decision up for grabs, the potential for friction between fellow parents is high.

In one case Ms. Warner cites, one woman "remembers clearly when she reached the breaking point with close friends." Not only did the friends set a 6 p.m. bedtime for their preschool son, but they also banned all plastic toys and instituted a naturopath-recommended diet of staples such as "raw parsnips, duck eggs, sunflower butter."

"In the end, it was a birthday cake that did her in. The dad baked it — 'some kind of spelt hoecake,' she recalled. As a memory formed of the little boy, once joyfully eating chocolate cake and ice cream, she lost it. "I said: 'This is insane. This is bordering on abuse. I can't take it anymore! I love him, and I think he deserves a birthday cake!' " writes Ms. Warner.

To explain why these scenarios can cut so deeply, Ms. Warner invokes a psychoanalytical theory from the 1970s, which suggested there were "ghosts in the nursery," which led people to parent based on insecurities and emotions stemming from their own childhood.

Parenting seems to provide the ultimate do-over, goes the theory. No wonder we're sensitive if a friend doesn't get it.

Furthermore, today, decisions about breastfeeding, food choices and the like have morphed to take on the weight of political, moral and ethical stances, Ms. Warner writes.

Her piece also goes a long way in explaining the tight bonds many new moms make with each other as they self-select new friends with similar views at the playground.

Have you ever found yourself at odds with a friend's parenting style? Have you ever felt judged for yours?