Young, in Love and Sharing Everything, Including a Password

“We did it so I could check his messages because I didn’t trust him, which is not healthy,” she conceded.

Counselors typically advise against the practice, and parents often preach the wisdom of password privacy. Winifred Lender, a child psychologist in Santa Barbara, had her three sons sign “digital contracts” that outline terms for how much media they will consume, how they will behave online and that they will not share passwords. Still, Ms. Lender said, her 14-year-old was recently asked by a friend for his password.

“He said: ‘You give me yours and I’ll give you mine.’ ”

Her son was taken aback but then relied on a tried-and-true excuse for saying no. “He blamed it on his parents,” Ms. Lender said of her son. “He said, ‘If I give you my password, my mom will have a cow.’ ”

Emily Cole, 16, a high school junior in Glastonbury, Conn., felt the sting of password betrayal in seventh grade, when she gave her e-mail password to her first boyfriend.

Then she started to develop feelings for another student, she said, and sent an e-mail to her. Her boyfriend read the e-mail and started spreading it around the school, calling Ms. Cole a “pervert.”

Ms. Cole said it was deeply hurtful. And yet, despite what happened, she said she would not have reservations about sharing her password with her new boyfriend.

“I know this sounds kind of weird, but we have a different relationship,” she said. “We’re not in seventh grade. I trust him in a different way, I suppose.”

Ms. Cole’s mother, Patti, 48, a child psychologist, said she believed her daughter would be more judicious now about sharing a password. But, more broadly, she thinks young people are sometimes drawn to such behavior as they might be toward sex, in part because parents and others warn them against doing so.

“What worries me is we haven’t done a very good job at stopping kids from having sex,” she said. “So I’m not real confident about how much we can change this behavior.”