Perhaps my two “bio” sons, Seth and Lee, then 23 and 20, had looked into erotica, but they’d come of age in an epoch closer to the lifetimes of Thomas Edison and the Wright brothers. When they were young teenagers, computers were old, slow and black-and-white, more toaster or window fan than science fiction portal into every crevice of the known universe. When they were young, sexy and forbidden images were reproduced in magazines and also arrived in the mail in the Sports Illustrated swimsuit issue or the Victoria’s Secret catalog. To conceal testosterone-fueled research from his mother, a 20th-century boy shoved his magazines deep under his bed, in the moldering twilight company of old socks, chewed gum and misplaced homework. No electronic trail lingered. Twenty-first century boys are unlucky in this way.

By sundown on the day I discovered the new research interest, “saxing,” I had purchased and downloaded a software product called NetNanny. Any attempt to visit a website featuring a female other than Cinderella, Indira Gandhi, Julia Child or Prime Minister Margaret Thatcher was blocked by the sudden appearance, in profile, of a British housekeeper in a white apron, starched collar and little peaked hat. In her hand she held up, victoriously, a computer mouse that she’d evidently just cheerfully yet violently yanked out of the back of somebody’s hard-drive.

I was really smug about Net Nanny for two months.

The four younger boys were stymied by NetNanny for a day and a half. A clever friend of theirs secretly taught them how to turn off my computer, turn it back on, and quickly create a “guest” account other than mine. My computer “guest” was named “Franny,” in honor of our stocky middle-aged rat terrier. On Franny’s account, there was no Net Nanny and there was no Mom but there were, however, plenty of fleshy, top-heavy, rouged and evidently outgoing young women.

I may not be of the Internet generation, but even I know that a rat terrier would have no interest in a computer guest account. Wordlessly I retaliated with stricter software than NetNanny. The new protective software was called Safe Eyes. Safe Eyes stopped young teenage boys from accessing any website other than one entitled www.FunWithFractions.com.

So the boys down-shifted to other media.

One day a $767 bill arrived from our cell phone carrier. Close scrutiny revealed that the excess charges arose from the boys’ cell phone numbers: hard-core sex scenes had been downloaded from the Internet onto the tiny screens.

“I didn’t know they had Internet access on their phones,” I protested to Customer Service (not wanting to mention, “I didn’t know you could even get two female breasts on such tiny screens.”) What I did say was: “They told me they needed cell phones so they could call when soccer practice was over!” Hadn’t each portrayed himself as at risk of abandonment, alone and fearful on a darkening and vast soccer field as night closed in, long after the parents of boys with cell phones had come and gone? Customer Service waived the charges because the boys were not supposed to have Internet access on their mobile phones.

So that portal was closed. But the boys journeyed on.

A cable TV bill arrived from Comcast, charging us for a pay-per-view purchase of an X-rated movie about pole-dancing.

Pole-dancing is not, I recently learned, the festive springtime event of European folk culture in which young girls hold ribbons and weave in and out around a central post, wrapping it in a rainbow of pretty colors while adult males in short pants and knee socks whistle into wooden flutes. That is “Maypole dancing.” Pole-dancing is another thing entirely. I am learning so much!

When I checked the date on the Comcast bill, I realized I’d had a middle-school son home sick on that very day. At the precise hour of the movie screening, he’d been “napping” on the basement sofa, in front of the big-screen rec-room TV, upon which non-Maypole dancing was being anthropologically examined.

Furious with the $20 fee, I pounded down the stairs, found this son, and held out the bill to him. “This was the day you were home sick. That was your movie and it cost us $20! What are you going to do about it?”

“Oh, OK,” he said mildly. He slipped into his bedroom, removed his wallet from a drawer, took out a twenty and handed it to me.

Mollified, I couldn’t think of anything to say other than: “Hey, thanks!”

Back upstairs in the kitchen I had misgivings, which I shared with my husband, Don Samuel, a criminal defense attorney. “I’m not positive,” I said, “but I think that I just sold our 14-year-old son pornography.”

“That’s not good,” said Donny.

To which I replied: “I feel like his pimp.”

Of course we tried “Parental Controls” on the television.

“Parental Controls” should have the subtitle: “Ask Your Kids to Show You How to Install These Things.” The only Parental Controls we ever successfully set up on a television blocked nothing the children ever wanted to view, but resulted in our being unable to ever watch the “Jim Lehrer Newshour” on that set.

Thus, it should not have been an enormous surprise when, on a Saturday afternoon in August, another cable TV bill arrived, this one charging $120 for unsanctioned pay-per-view purchases, through the cable box in the basement, of XXX-rated movies involving, variously, lingerie, lesbians, Las Vegas and — no doubt — the Kama Sutra and perhaps even Virginia.

This time I was really mad. We’d had the excruciating and one-sided discussions about relationships, true intimacy and respect for women. I’d held these conversations (or “monologues”) with our daughters and I’d held them with our sons, because my husband (defender of the criminally charged) is incapable of allowing such delicate topics to cross his pure lips. I explained how demeaning it is to women to be perceived as sex objects; I touched upon the importance of respect in the approach to intimacy and marital happiness. The night I sat on the edge of 13-year-old Sol’s bed to broach the subject, he fell straight backwards onto his pillow as if he’d been shot, and then reached out and pulled the bedspread up and over his face, refusing to reappear.

On the afternoon that the pay-per-view bill arrived, the four younger boys and friends were lounging around the kitchen table eating cold cereal and popsicles.

“I need to talk to the Samuel boys RIGHT NOW,” I announced, the bill shaking in my grip as if I’d just grabbed a live duck out of the air.

The boys’ friends evacuated.

Twelve-year-old Helen peeked in, wondering if she were needed.

“I said the Samuel BOYS!” I roared. Helen fled.

I smashed the fluttering bill flat onto the table. “One hundred twenty dollars!” I shouted. “Who is going to pay for this?”

Daniel and Yosef, who’d lived in America for less than a year, instantly lost all English-speaking ability.

Sol put up both hands in self-defense and shook his head no. He glanced around with a shocked and concerned expression, as if startled to find himself in such low company.

Jesse, the Bulgarian 13-year-old who was somehow constantly in hot water, sighed and coolly raised one finger as if signaling a waiter to bring the check. “It was me,” he said.

“Really?” I asked, stunned at the rapidity of the confession. “All the movies? You?”

He sighed again. “Yep.”

“Jesse, that is a ton of money.”

He tsked sadly in regret at his own behavior and said, “I know.” He shook his head, as if to say, What am I going to do with myself?

“Go get your allowance book,” I snapped. He handed over the account register while his three brothers watched expressionlessly. “This will take you till … December to pay back,” I said. “You’ve got no spending money till then.”

“OK, Mom.”

“Can we go?” asked Sol, eager to put distance between himself and this distasteful subject.

“Go.” I waved the others away.

In a minute, Sol was back. For the second time in a three-month period, he was removing a $20 bill from his wallet and handing it to me.

“What’s this for?” I asked.

“To help Jesse.”

“Really?” I asked, startled. I was touched.

“Here, Mom,” said Daniel, having regained a few words of English. “Help Jesse.” He gave me a ten.

Yosef then produced $40. “Yosef, sweetie! You don’t have to do this.”

He shrugged modestly as I kissed him.

“Jess, sheesh! You’ve got nice brothers,” I said. “You’ll be able to pay off the rest of the bill easily.”

With a lump in my throat and tears in my eyes from these fraternal kindnesses, I made my way to the front room, where Donny reclined in his overstuffed chair reading his law books. “You will not believe what just happened. We have incredibly sweet boys!” I told him about the money they’d donated to Jesse’s case without anyone asking for it.

Donny glanced up from “The Eleventh Circuit Criminal Handbook,” said, “They watched the movies, too,” and returned to his reading.

Why? Why am I such an idiot? I’ve been raising children for decades, and this insight would never have occurred to me.

The next day I found Jesse eating a bowl of Froot Loops alone in the kitchen. “Jess,” I said, “those movies … Did any of the other boys watch them with you?”

“Mom! Are you kidding me? I didn’t watch any of them! Did you see the times those movies were ordered?? Five in the morning! They watch them before school. I don’t get up that early!”

It was true. My sons from Ethiopia, who’d once worked as goatherds, were up at dawn every day.

I sputtered to reply. “Well … why did you say it was you?”

“Did you see their faces? They were terrified,” he said, and returned to his Froot Loops.

When I relayed this news to Donny, he laughed and said, “They must have been thinking, ‘Jesse’s always in trouble. Jesse can take the heat.’”

I’m a sucker for sibling solidarity. To celebrate Jesse’s having paid off his bill and the spirit of fraternity that helped him do it, I took the kids to a movie. I took the six youngest males and females to the Disney-Pixar animated movie, “Wall-E.” “Thanks, Mom!” “That was really fun, Mom!” everyone said when we got home from our big night out. The two girls headed upstairs to their bedrooms, and the four boys ran for the basement stairs.

Excerpted from No Biking in the House Without a Helmet by Melissa Fay Greene. Copyright © 2011 by Melissa Fay Greene. Published May 2011 by Sarah Crichton Books / Farrar, Straus and Giroux, LLC. All rights reserved.