It all started when Jane's parents met another couple at a party back in 1965. With so much in common, her parents and the other couple each had two girls of similar ages. Jane was four and shared the same birthday with the other couple's youngest daughter, Jenny who was five. Their elder sisters were of the same age too. The two families grew close, and for the next few months, were inseparable.

However, Jane and Jenny's lives went downhill after their parents decided to switch partners. She writes: "In less than nine months, two new couples had formed: my father Edward and their mother Helen; my mother Rosemary and their father Paul."

The two new families were then separated at opposite sides of the world, but still kept in touch via letters and photos. The separation had sparked a silent rivalry between the author, Jane and Jenny, each believing that the other stole each girl's father, and each competing for their father's acknowledgements and appraisal, each girl trying to prove that she's better than the other.

Jane's and Jenny's jealousy and rivalry slowly transformed them into self-destructive ways after Jenny's father left Jane's mother. They got involved with alcohol and got into trouble with boys. Both girls would also slit their wrists and hurt themselves. Eventually, Jenny took the turn for the worst, dropping out of school and using drugs, while Jane drank and slept with random guys.

However, Jane managed to graduate from Princeton with honours, moved, wrote a novel, and got married. One day, about 33 years after their parents swapped partners, Jane's father called and told her that Jenny was dead. Jane writes: "It turned out that Jenny had gone through rapid detox, but then apparently stopped taking the antidepressants she had needed to endure this and sank. By then, even the little heroin she injected was too much."

It was indeed, when Jane's mother caught a glimpse of her husband embrace Jenny's mother, when their sad tale began.

My parents swapped partners with their friends and destroyed my life [DailyMail]