Since she was 12 years old, Niamh McKevitt has been the only girl in the whole of England playing boys' football in her age-group.She has become used to the sarcastic remarks from sniggering opponents and their parents as she lines up to play, but by the time she's gone in for her first crunching tackle the laughing has usually stopped. By the end of the game her gender has invariably been forgotten - she is, quite simply, a very good footballer.Along the way, Niamh has fought the football authorities, schools and numerous teachers and coaches who all insisted she should stick to playing with girls.Undeterred, she not only broke stereotypes, but went on to become the key subject of an FA research project into mixed football. As a direct result, the FA continued to change their rules and girls are now allowed to play with boys up to under 18 level.In 2015, while still at school, she made her debut in the Women's Premier League and she has also represented the Republic of Ireland Women at junior international level.Niamh's success challenges the widely held belief that girls will become better players if separated from boys, and calls into question the entire coaching and development structure for women's football - the fastest growing participation sport in England. But beyond the gender politics, Playing with the Boys is quite simply the inspirational story of a girl who loves football and her unique battle to become the very best player she can be.