JACKIE KLEIN is a devoted mother of two little boys in the suburbs of Portland, Ore. She spends hours ferrying them to soccer and Cub Scouts. She reads child-development books. She can emulate one of those pitch-perfect calm maternal tones to warn, “You’re making bad choices” when, say, someone doesn’t want to brush his teeth.

That is 90 percent of the time. Then there is the other 10 percent, when, she admits, “I have become totally frustrated and lost control of myself.”

It can happen during weeks and weeks and weeks of no camp in the summer, or at the end of a long day at home  just as adult peace is within her grasp  when the 7- or 9-year-old won’t go to sleep.

And then she yells.

“This is ridiculous! I’ve been doing things all day for you!”

Many in today’s pregnancy-flaunting, soccer-cheering, organic-snack-proffering generation of parents would never spank their children. We congratulate our toddlers for blowing their nose (“Good job!”), we friend our teenagers (literally and virtually), we spend hours teaching our elementary-school offspring how to understand their feelings. But, incongruously and with regularity, this is a generation that yells.