In particular, they found cats don't suffer from separation anxiety and any noise they make when their owner leaves is more likely to be out of boredom or frustration.
Autistic people can have special skills but they also tend to suffer from anxiety, obsessive behaviour and other problems that far outweigh any advantages.
Although many people do not think of homosexual relationships as resulting in a family, it has been estimated that about one of five gays and one of three lesbians enter a homosexual marriage.
Undiagnosed and treated postpartum depression "causes enormous distress to the family, and it can have long-lasting consequences for the child, " said Meltzer-Brody.
When acacia trees are grazed by animals, they quickly react by producing chemicals called tannins, which make their leaves unappetizing and tough to digest.
Drag is the force of air resistance pushing against a ball's motion and slowing it down, while lift is a force causing a ball to swerve off a straight path.