Vanishing World by Sayaka Murata (Paperback)

Amane is ten years old when she discovers she's not like everyone else. Her school friends were all conceived the normal way, by artificial insemination, and raised in the normal way, by parents in 'clean', sexless marriages. But Amane's parents committed the ultimate taboo: they fell in love, had sex and procreated. As Amane grows up and enters adulthood, she does her best to fit in and live her