My childhood was complicated. My father left when I was a few months old and my mother died just before my 13th birthday. She went into hospital to have a baby and I never saw her again. No one knows why she or the baby died. I tried to find out when I was pregnant, 22 years later, but the hospital had changed hands and the records of her death had been lost.

My stepfather looked after me but quickly remarried. My stepmother had already been married twice and had children living elsewhere. It was a miserable time and I more or less left home at 16. My friends became my family.

In September 2009, when I was 42, I was reading The Glass Palace by Amitav Ghosh, which a friend had recommended as some of the story is based in Burma, and my mother was Burmese. I remembered her talking about some of the places mentioned in the book and I started searching for them online. Looking at the Shwedagon Pagoda, I randomly followed a link to a Burmese missing persons forum. The posts were fascinating vignettes of people’s lives, and I stayed on the forum for about an hour. I was about to go to bed when I saw a message that said: “I am looking for my mother Mary, born in 1946.” It was my mother’s name and year of birth. The person who had posted the message also said she was looking for a sister who had my birthday.

My heart was beating so fast that I didn’t read the rest of the post. No one had ever mentioned that I had a half-sister. It seemed unreal, but I had no doubt it was about my mother and me. My only concern was that it was either a scam or, if this person really was my sister, she may want something from me. It sounds selfish, but my life felt stable and I was fearful of unsettling it. If she asked me for money or a kidney, I’d be unable to say no.

I decided to give her a chance, though. At the very least, I could tell her that our mother had died. I filled out a contact page with my details, creating a new email account for replies. I said, “I am responding to your post. I think I am your sister. I am really sorry to say that our mother died in 1980 in childbirth.”

I went to bed, and a few hours later my mobile pinged in response. I was still suspicious (and she told me later her husband had been worried my reply might be a scam), but almost as soon as we started communicating, we were both reassured.

We emailed each other at first. She lived in Hong Kong, her name was Ann and she was born two years after me, but adopted as a baby. I have no recollection of that time, but she knew our details because she had copies of the adoption papers. There was no mention of who her father was.

Eventually we started talking on the phone, catching up on our lives, and two months after I’d spotted her post, in November 2009, we met at a hotel near Windsor. I was excited and extremely tense, but it wasn’t like one of those TV shows because, strangely, I didn’t feel that emotional and we kept our distance. But I did keep looking at her and seeing glimpses of my mother, which was lovely.

We went for a walk in a nearby park and chatted about our respective childhoods. She grew up in the Midlands and had a much more stable upbringing than mine. She had posted on the forum seven years earlier, out of curiosity, then had forgotten about it. In the interim, she had married and moved abroad, but before she did so, she used to live 15 minutes from me. We even have a couple of friends in common. I don’t regret that we didn’t meet earlier, though: it felt like exactly the right time, after we were both settled.

We don’t have a close relationship, because we live so far away from each other. We email but I see her only once a year, when she comes over to catch up with her family and mine. My children already have 11 cousins on my husband’s side but I love that Ann’s children are my blood.

The whole experience feels so far-fetched. I can’t believe we found each other. I don’t think so much about my sister and me, though, as about how sad it was for my mother having to give up her child. I think she would have been pleased to know we found each other.

• As told to Kate Morris

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