Former Sunderland winger Adam Johnson told a court on Tuesday that a picture taken of his penis on his phone was for medical purposes.
The 28-year-old is on trial at Bradford Crown Court over two counts of sexual activity with a girl under the age of 16.
Johnson, who denies the charges, is alleged to have taken part in a sex act with a 15-year-old girl while the pair were in his parked car last January.
During questioning by Johnson's QC Orlando Pownall, a photo of the sportsman's exposed penis was shown to the jury.
The picture was taken on the accused's phone in August 2013.
Mr Pownall QC said, "It is not being suggested that this picture was taken for fun or that you were going to send it to someone," to which Johnson answered: "No."
The footballer's lawyer continued: "Did you take photos at different times of what I am going to describe as your nether regions? Why?"
Johnson replied: "To show the doctor."
Mr Pownall QC told the court: "We'll leave it at that."
Johnson also revealed that he lied to police when he told them that he did not have "feelings" for the teenage girl.
The footballer has pleaded guilty to one count of sexual activity with a child and a further count of grooming.