Let's switch from talking about race and gender and use the words "Insiders" and "Outsiders" and think of a big structure, we'll callit "The Keep."

I think the first and most urgent job is to change cultural assumptions amongst the insiders. If they are thinking that outsiders aren't biologically inclined towards living in a keep, not qualified to maintain a keep, &c., that's a huge barrier, a moat if you will.

So we remove that. The next problem is that even with the moat gone, the outsiders fear being uncomfortable inside, whether from being one of a very few outsiders amongst a lot of insiders or from other outsiders resenting them moving into the keep.

I think it's important to remove those sources of discomfort and to actively encourage outsiders to consider moving inside so that we get all of those who woud like to come inside but fear unpleasant consequences.

After that, I don't think we need to try to convince people who like living outside to come in. Let them be happy outside! But I do think we should remove barriers to coming inside and encourage coming inside to counteract any fears of negative consequences for those who would otherwise like to come into the Keep.