Dear Grandparenting: I got a cardiac check-up yesterday, minus the doctor. I walked in on my granddaughter and her boyfriend doing what looked to be having sex under a blanket. My heart rate went straight through the roof

It took a while to regain my composure. I returned to the room with a little speech all prepared but they were long gone.

She phoned me later that day to apologize for embarrassing and begged me not to tell her parents because they don’t like her boyfriend. My son has had already words with him. I am not a real big fan either. He hardly ever bothers to say anything and doesn’t clean up after himself around the house.

My granddaughter is 17. I gave her a house key because her parents don’t always get along. She feels “safe” in my place. Do I tell her parents or let it slide? My granddaughter promised I would not be seeing Tom anymore. What next? Bess Kendi, San Bernardino, California

Dear Bess: How many parents still sit their children down for “the birds and the bees” chat? In today’s hyper-sexualized youth culture, we suspect most grandchildren learn about the mechanics of the act rather early on. Sex is on the tip of young tongues, a few clicks away on the Internet.

Like it or not, many are not saving themselves for marriage. According to recent federal government data, 55 percent of male and female teens have their sexual initiation by age 18. While we certainly don’t endorse such romps, we know plenty who regard them with a certain air of inevitability.

Government data offers good news too. The percentage of sexually experienced teens is declining, while females overwhelmingly insist on contraception. The most common reasons teens abstain are “it was against religion or morals,” “haven’t found the right person,” and “don’t want to get (a female) pregnant.”

What’s a grandparent to do? Even if it’s too late for the birds and the bees, it’s never too late to discuss the risks and consequences of loose behavior. At that age, grandchildren think they know it all. Bad things only happen to other people, right? Wrong!

Grand remark of the week

G.E. Downs from Lancaster, Pennsylvania was a whole lot more excited about the impending arrival of another grandchild than grandson Robbie was at age six.

“You’ll either have two brothers and one sister or two sisters and one brother,” said G.E. “Isn’t that great?”

Robbie wasn’t buying it. “I kept begging Mom and Dad to get me a dog or a snake and they go and have a baby instead.”