My husband had the letter waiting for me when I returned from visiting my dad, who is sick in Chicago. It was about midnight. I was tired and sad, but then suddenly hysterically I was sobbing with joy.

“Life! Life! Oh, my God, Joe! I can save a life!”

The letter was from the National Marrow Donor Program the folks who match up terminally ill patients with strangers who, miraculously, happen to share the same one-in-a-million bone marrow type.

“Dear Lenore,” it said. “You joined the National Marrow Donor Program last year. You now appear to be a match for a 17-year-old boy with acute leukemia in need of a transplant. The transplant center is requesting you go for further blood work. If you are the best match for him, they will ask you to donate stem cells. To arrange an appointment, please call us.”

Call ’em? I couldn’t wait! It was impossible to fall asleep.

The next morning I flew into work and waved around my letter: “Look!” I bragged. “I get to save a 17-year-old’s life!”

I called my mom in Chicago to lighten the gloom. “Hey, mom, guess what?”

“Life, life, life!” I kept crowing, and here’s what I got back:

“I’ve heard it’s very painful.”

Painful? I stopped mid-crow. What had I gotten myself into?

Well, I started doing a little research and found that patients who are sick enough to need a bone marrow transplant have exhausted their other options. With a transplant, they’ve got a 40 percent to 60 percent chance of survival. Without one, they die.

That was enough to perk up my interest again, so I called to make the follow-up appointment. While I had the marrow mavens on the line, I asked for more details about “my” 17-year-old.

Forget it. They couldn’t tell me anything his name, his country that’s all confidential. If he lives for a year after the donation, then I’ll get to meet him.

Oh, my. If he lives. And he’s only 17. I’ve got sons of my own, little ones. And as hard as it was to think about that young man slipping away, it was even harder to think about what his parents must be going through.

So I didn’t. I thought about me! And pain. And that night, I didn’t sleep again.

Next morning, I took the blood test a snap and was told it could take up to three months before the doctors decide if I’m in. It depends on whether I’m the best match … and whether the boy lives until the transplant.

I also learned how the donation is done: Under local or general anesthesia, the doctor inserts a needle into the hip (mine, that is) and extracts some marrow the stem cells that eventually grow into blood cells.

These are needed because the boy will have undergone such devastating treatment to kill his cancer that he’ll be near death himself, lacking even the ability to make blood. So my cells will do it for him.

And, yes, it will hurt. Him, a lot. Me, much less. Supposedly, for the donor it’s no worse than a slip on the sidewalk. One of the guys who runs the program came in to talk to me because he’d given marrow for a 13-year-old girl, “And I was playing softball four days later.”

“Did you eventually meet your recipient?” I asked.

No. She died.

So now it’s looking as if there isn’t even a choice to agonize over: On one side of the scales, there’s me with a sore hip and kudos galore. On the other side, there’s a kid who may get to live. Case closed. As nervous as I am, I hope I get to give.

If you want that chance, too, get in touch with your local medical groups.

In the meantime, pray for “my” kid.

Lenore Skenazy’s e-mail is

lskenazy@edit.nydailynews.com.