Children diagnosed as transgender could be autistic, a controversial psychologist believes.

Latest figures show that the number of children under 10 in Britain being referred to the NHS over transgender feelings has quadrupled in five years.

One psychologist says these youngsters are seven times more likely to be on the autistic spectrum.

Dr Kenneth Zucker believes autistic traits of "fixating" on issues could convince children they are the wrong sex.

He makes the claims in a BBC 2 documentary on Thursday at 9pm called Transgender Kids: Who Knows Best?