Bryan Johnson, who is 47, has spent millions trying to keep his body young
The son of a biohacker has spent millions trying to keep his body young has responded after an 'erection test' between him and his father went viral. Bryan Johnson is a 47-year-old biohacker and entrepreneur who, for the pasr five years, has spent more than $2 million (£1.6 million) on trying to reverse his physical aging process.