Then, three and a half years ago, I got a call from the identical twin sister I never knew I had. Each of us had been adopted and raised by separate families — neither of which were informed that their new bouncing baby girl was part of a matched set.

That was strange enough, but once my twin and I started doing research about why we had been separated, we found that we had briefly been part of a twins study on the age-old topic of nature vs. nurture.

Which led, as you might imagine, to the memoir (co-written with my sister, Elyse Schein).

In it, we investigate the reason for our separation and the emotionally turbulent process of eventually getting to know each other as adult sisters who never had a childhood. While our reunion was joyful, it was not always easy. Apparently, having identical DNA did not guarantee that we would understand one another.

In writing the book — “Identical Strangers: A Memoir of Twins Separated and Reunited” (Random House) — I made a concerted effort to portray myself realistically, warts-and-all. Now I worry that perhaps I was too realistic. Maybe not everyone — even my longtime Park Slope neighbors — will find my “character” sympathetic. They might not understand my initial reluctance to be a twin or my hesitance to seek out my biological family.

With the memoir about to hit bookstores — and the requisite reading at the Barnes and Noble on October 24 — I am trying to reconcile myself to the fact that strangers, acquaintances and friends will know as much about me and my hang-ups as my therapist. Of course, I want people to read the book, but I am wary of the attention my newly gained notoriety will inevitably bring.

Am I prepared for my favorite waitress at Two Boots to ask if I am still taking anti-depressants or for the helpful saleswoman at Otto to analyze my relationship with my sister? I dread the thought of neighborhood moms shaking their heads and clucking behind my back at Tea Lounge after reading all about my abandonment issues.

In reality, our book is not a juicy tell-all, but rather an exploration of what it feels like to discover that you’re an identical twin. Elyse and I grappled with the age-old question: what is it that makes us who we are?

Funny, but during all these years when I thought my life was too dull to write about, I had no idea that I would end up co-writing a memoir with my identical twin.

And now that I know her, I realize I couldn’t have written my own life’s story without her.

Paula Bernstein is a writer/journalist who lives in Park Slope.