How much human population do you need to support same sex relations?

This may be a math problem, but I'm curious if any can answer this question since it kinda came up in one of my storys : homosexuals are maybe 1.6 (according to wiki) percent of the population. So the question is: how many people do you need to gather into one area for Homosexuals to be able to reliably find a person who is ALSO homosexual (and of the same sex) within there area? lets leave aside cultural stigmas and hurdles they may face, lets talk numbers here. how big a city do you need for people to find same sex partners given the relatively small percentage of the population they make up.

Going by your numbers.... well I'll be lazy and round to whole numbers for upper and lower limits

Using the high point of 2%, that's one person in 50, so one hundred will give you two. Assume even ratio of the genders and that gives you two hundred people. The lower bound of 1% doubles the number of people of needed for a total of four hundred.

But that's not taking into other factors like age distribution. Does no good if ones pre-pubescent while the other's got one foot in the grave from old age. So, pulling a factor of ten out of the air, you're probably looking at something like 4000 or more, and even that's likely to involve a fair bit of exogamy due to compatibility and personality factors that are less amenable to statistical analysis.

Following with the previous poster's mathematics, it would appear that a community of 4000 humans might have 80 homosexuals. Let's further assume that 40 of them are male, and forty are female. Now, we're getting to group dynamics and this is where your setting will be important. Even if the homosexuals aren't persecuted, if they're in any way considered 'the other', their social cohesion will be much stronger, so you can quite reliably have a group of 10 gay men who will all know each other and probably be friends. If, on the other hand, homosexuality is no big deal, then the personal differences between group members will be more visible and cohesion will drop.

So, rule of thumb, the 'otherized' group will have an upper limit of appx. 10 individuals before differences start eroding group cohesion, while a more accepted group will have a lower upper limit. Hope it helps.

The crucial phrase here is "find", I think, and I am of the mind that it's not exactly a math problem when you're counting on humans to act a certain way.

In theory, so long as there are two or more homosexuals (of the same type - we'll assume a pair o' dudes for now) in any group, the possibility exists that they can find one another. The question here isn't "how many" so much as "how", and for the sake of actually constructing an argument we'll sidestep the "use Grindr duh" response.

Taking that 1.6% at face value, the straight algebra answer is that you'd need a population of 125 dudes minimum for two of them to find love together. The "how" here is that a town that small isn't going to have many secrets, and it's not unreasonable to assume they'd already know who the lifelong bachelor(ette)s are.

That percentage seems a bit low, though, and if we're looking at the same wiki page it only refers to people who identify as gay or lesbian. This is a separate question from whether or not they would enter into a homosexual relationship, and that would include at least the .7% of people who identify as bisexual as well as anyone who'd consider themselves "X with an exception". The generally quoted number of "about 4% of the population" seems more right for this sort of thing, I think.

Of course, this all ignores the reputation (SF), total population (NYC), geographical area (Jacksonville, FL), and reception (CA, in really general terms) a place may have, which further skew the necessary total population one way or the other.

It's an irritatingly difficult question, to be honest.

I'm an idiot, so rather than math, I'll present you with my own form of genius. The kind of genius you may see in a dog chasing its tail, or a cat fearing for its life at the sight of the deadly living room vacuum. So, basically, remember that the fictional world can break numbers. It can break reality. You can change reputation, population, location, size, etc. You break all of this already by even creating characters in a real setting.

So, basically, change the numbers if you'd need to. The people above gave you the answer you're already looking for, and they gave very well-written answers. However, numbers can make things harder. Simplicity can make things a lot easier, and can help you with whatever you're planning. However, remember some things. Not all people that experiment are gay, many that are gay may be in the closet, and many homosexuals may all be in one spot at once, such as at gay bars.

But generally, I recommend doing whatever you want. You can change the numbers, use the numbers, or take other things into factor, but just have fun with writing homosexual characters. They're not different people for being gay, but writing their love lives is very interesting, in my opinion. Just try to write a gay character like you'd write a straight character. Straight or gay does not make them who they are, they make themselves with their personality, their sexuality comes second.

I think bisexuality would be much easier to maintain. I would imagine that any society that was dominated by homosexuality would eventually become dominated by bisexuality out of necessity.

Problem with the question is assuming that there are only homosexuals and heterosexuals as options. No matter if homosexuals are really only 2% (I read other numbers that put them around 10-15%) if you're talking about "pure" homosexuals (people that do not feel absolutely any atraction toward the other genre) which I think are not so much. But if you include bisexuals, pansexuals and heteroflexibles that can have relationship with "pure" homosexuals and among themselves, then the number increases drastically.

You also need to consider what forms of relationships are acceptable and what are taboo, because cultural expectations are incredibly powerful influences on behavior.

For example, if monogamy is the expected normal for relationships, then people who may be interested in polyamory, or open relationships, or even just remaining unattached may instead take on a type of relationship that they wouldn't otherwise choose.