This article by Ed Yong explains how he has been actively trying to redress the gender imbalance in his articles by searching for more women to interview and publishing more quotes from women in that industry, after he realised that, completely without thinking about it, he just tended to include a lot more men in his stories, and his presentations - mainly because they were the people he knew and would hang out with.
What has that got to do with sales? Well, investing a little time in 'not-pissing-people-off' is a great way to expand the market.
It turned out for Ed Yong that there were plenty of other experts in the field, and that talking with and quoting the whole range would make Yong's work more attractive and accessible to a whole lot of extra people.
The same can work with lots of groups of people.
My gay friends don't need to see a specialist gay insurance adviser, they want to see a good insurance adviser, who doesn't annoy them by being obviously uncomfortable with their sexuality, or worse, being rude about it. Pretty much the same as heterosexual people, really.
Barriers of race and culture may be stronger in our minds than they are in practice. Widespread beliefs that 'Chinese' people don't buy life insurance have been completely destroyed by research. The fact is that there in many, many, thousands of policies. If you don't have many Chinese clients, it's more likely to be a marketing issue with you, than a buying issue with them.
With a few small changes to make a service more inclusive we can go from being crossed off the list of people being considered, to being included, and even preferred as a supplier. Think of it as removing barriers to people seeing and appreciating your real expertise, and it becomes a whole lot easier.