Remember Their Birthdays? Forget It : Mother’s Day is the second Sunday of May, and therefore falls near Mom’s birthday, which I’m pretty sure is on the 9th, unless that’s my brother’s birthday.

The telephone rang Friday night. As I should have known, it was Mom.

“You’re coming to Jackie’s tomorrow, aren’t you?”

Yes, Mommy Dearest. For the hundredth time, yes.

OK, maybe it was only the third time. Regardless, I had not forgotten that Jackie, my brother’s mother-in-law, was having everybody over to celebrate two (or possibly three) birthdays, one (or possibly two) wedding anniversaries and, of course, Mother’s Day.

For the former Helen Jean Duke of Birmingham, Ala., it was a twofer. Mother’s Day is the second Sunday of May, and therefore it always falls near Mom’s birthday, which I’m pretty sure is on the 9th, unless that’s my brother’s birthday. His, I’m pretty sure, is the 4th. (Lately I’ve tried to remember it as Cinco De Mayo Eve.)

By now you’d think I’d know all these family occasions by heart, but Mom, bless her, is very understanding. That’s why she gives her youngest little reminders. It’s not that she’s greedy for gifts. She just wants to spare her boy the embarrassment and shame he’s suffered in years past. Suffice it to say that in the Harris family, my forgetfulness is legendary. Time was when my sister Linda and brother Dusty (but especially Linda) would berate me for being a spoiled little brat who cared about nobody’s birthday but his own.

But Mom was kind. What others saw as self-absorption Mom saw as a kind of learning disability, something we’d all just have to learn to live with. After all, her youngest also happens to be color-blind.

Indeed, Mom forgave me before I learned to forgive myself. My guilty suspicion was that maybe Linda and Dusty were right about me all along.

Lately, however, I’ve been able to come to peace with myself, having arrived at a fresh understanding about why I’m so bad about remembering family birthdays. Unlike color-blindness, this problem isn’t something I was born with. And, no matter what my siblings say, it isn’t the result of an overweening ego.

It is, in fact, the residue of childhood trauma. It’s odd I didn’t realize this earlier. You don’t have to be Freud to figure this one out.

It happened when I was 4 years old. Linda would have been 8 and Dusty 7. I remember it very well indeed.

“You aren’t really our brother,” Linda told me. “You were adopted.”

“I am not,” I said.

“Are too,” they replied.

They proceeded to describe the day I joined the family with great and convincing detail. Linda explained how she and Dusty were traveling with Mom through the town of Timbuktu. It was there, she said, that Mom purchased me.

Linda even remembered the price.

“Two cents,” she said. “We were really mad. We could’ve each gotten a piece of bubble gum. Instead we got you .”

“Yeah,” Dusty sneered.

It must have been at about this point I started bawling. I called them liars and crawled under the dining room table, my favorite refuge when suffering the slings and arrows of baby brotherhood.

I was at an age when I looked to Dusty to protect me from bullies. And sometimes Linda was so nice that, when I suffered a nightmare, she’d let me crawl into her bed. (I’d outgrown running to Mom.) But now, as I blubbered away, they just laughed.

Mom came to my rescue. She scolded Linda and Dusty and assured me that I wasn’t adopted.

But I knew she would tell me that. And so the doubt must have lingered, a little gnawing question mark deep within my subconscious.

Over the years, this episode would come up time and again, evolving into a running family gag. Linda and Dusty (but especially Linda) still like to remind me I’m adopted. And often I like to remind them, as if the lack of genetic connection is a great relief.

But only recently has it dawned on me that this troubling event may very well explain my amnesia regarding family occasions. Could it be that a faint, irrational glimmer of doubt still exists? Or could it be that my subconscious is out to avenge this humiliating skirmish in my sibling warfare?

Whatever, the link seems clear. And it’s nice to be able to blame Linda and Dusty.

Saturday morning found me at the Glendale Galleria, finishing my shopping. A necklace caught my eye. I’m not sure about the color, but the clerk said it was Venetian glass and it was beautiful.

Mom liked it. And Dusty liked his gifts too. One was a little desktop ceramic of the Loch Ness Monster and the other was a set of bookends made from stone that had been cut and polished to a high gloss. “Geodes,” I think they’re called.

It didn’t seem necessary to tell him that I’d actually bought the bookends for Linda a few months back. When her birthday came up--it’s March 22, I think--I forgot all about them.

But at least I remembered to call. I got her answering machine and did a rendition of “Happy Birthday.”

” . . . You look like a monkey,” I sang, “and you smell like one too!”

I’m so glad Mom reminded me.

Scott Harris’ column appears Tuesdays, Thursdays and Sundays. Readers may write to Harris at the Times Valley Edition, 20000 Prairie St., Chatsworth, Calif. 91311. Please include a phone number. Address TimesLink or Prodigy e-mail to YQTU59A ( via the Internet: YQTU59A@prodigy.com).