To recruit more they need to make it more appealing for that type of group. Which is a hard slog, especially for .....
...an army which makes outsiders unwelcome.
"The majority of women in the British Armed Forces said they have been bullied, harassed and discriminated against.
A government inquiry into women in the armed forces heard traumatising "horror stories" that painted "a difficult picture of women in the military".
An almost unprecedented number of current and former serving women took part in the inquiry - 4,200 women (9% of the female military population)."
"A former paratrooper endured racial abuse and described racism as "prevalent" in his battalion, an employment tribunal heard.
Hani Gue told the tribunal he saw Nazi, Confederate and SS flags and photographs of Adolf Hitler displayed in accommodation at Colchester.
Mr Gue and colleague L/Cpl Nkululeko Zulu have taken the Ministry of Defence (MoD) to a tribunal alleging they suffered racial discrimination."
"When David Nkomo joined the Army in 2009 he was full of ambition. Awarded best recruit when he passed out of training age 23, he served one tour in Afghanistan with the Rifles. But four years later the career he had hoped for was over because he says he could no longer tolerate the racial harassment he'd been subjected to.
"I packed my bags and said I'm leaving. Getting out of the Army. I don't want to be here."
Regularly called "Black Dave" by his unit, to distinguish him from another Dave in the company, he says dark humour was a part of army culture.
"If it's just banter, it's just banter. I'll probably laugh at it 90% of the time," he says.
But while he tolerated the nickname, he says his experiences of discrimination went beyond casual banter to racial abuse by other soldiers. He says it went up the ranks and when he tried to raise his concerns, it made things worse.
"That's why a lot of people don't want to talk, because if you talk, your career is screwed."