95 per cent of parents have a favourite child, but few mothers and fathers would dream of admitting it, a new book has claimed. Writer Jeffrey Kluger, who dedicates a chapter of 'The Sibling Effect' to favouritism, believes those who don't admit to loving one child more are lying, reports the Daily Mail . "'It is my belief that 95 per cent of the parents in the world have a favourite child, and the other five per cent are lying," he writes. Kluger, however, plays safe so as to not upset his own daughters, aged eight and ten, adding: "The only exceptions are my wife and me." He says studies show that fathers are most likely to favour youngest daughters, while mothers are more prone to liking an eldest son best. Middle children, he reveals, are least likely to be a parent's favourite, unless they are the family's only son or daughter. But a child's sex and position in the family have less to do with parental favouritism, said Kluger. He says that it is natural for parents to search for likenesses in their offspring. "Having children is an act of genetic narcissism to begin with. We are hardwired to do it. What we look for in a child are traits that remind us of ourselves. You may love your husband, but it's your genes that are in play. You want the most direct portal for your genes in the following generation," he added.