Considering the fact that gays have become more and more accepted the last decades, probably yes. It's one of those progressive trends that just keeps going in western society. Segregation (not just by race, but religion, gender, etc.) has rapidly decreased since WW2, especially in western countries, and every generation seems to be more tolerant (or more individualistic, with tolerance as a result, that's another discussion) than the one that came before it. Only now do world leaders open up about it, and most of them have still grown up hiding it. A few years ago, the minister of finance in my country came out as gay, and even then there were some voices in his own party that shouted betrayal and called him a traitor (the party he belongs to is christian, but it's lost almost all religious influence the last 2-3 decades), asking for him to resign immediately. I'd say that the amount of gay world leaders will probably increase for at least the next two generations, as the ones that grow up without any prejudice will be the only ones with a good representation of gay people in places of power (which i expect to be equal in percentage as heterosexuals).
One thing to note is that the actual demographic facts about gay people are...not very reliable in most cases. I'm pretty sure that in my country it's estimated to be "somewhere between 5 and 10%", but even that might still change. A lot of countries are more repressive of gays than the one I live in, and googling gives me figures of something like 3% or less, depending on the country. With laws and general acceptance regarding gays rapidly changing, so do these figures, which makes any prediction difficult. My personal prediction regarding the amount of homosexual (and other non-heterosexuals) leaders for the coming 20-50 year, SHOULD NOTHING WEIRD HAPPEN (which might) is: Probably more.
Oh, and one more thing. I'm not sure how reliable this is, but I believe that there are more gay men than women, and google seems to back me up on this (again, unreliable data that may change in the coming years) This means that if we will see more women at the top, we might see slightly less gay people in those positions. Of course, this means that gay men should suppress women in order to get more influence up top, which would totally not be wrong or anything. If you only look at the leaders of each country, then you are of course looking at a small group, and luck/coincidence could definitely have drastic influence on the data. Especially when you consider that there are countries where a gay/female leader is not likely to happen anywhere in this century.
