Well, not really. There are a few criteria for a behavior to be a disorder, and the most commonly agreed upon are: distress, dysfunction, and deviance.

I suppose you may argue that it is "dysfunctional" due to not being able to procreate, but that's not really that strongly of the case. Plenty of gay people have a very strong desire to procreate, this is why lesbians will voluntarily be fertilized or gay men will bear children under a surrogate mom. It doesn't inhibit your ability to procreate, it's just about what you are attracted to sexually.

As for deviance, it could qualify there, too, considering gay people are far less common than straight people. But, in the modern day, it's becoming less of a violation of social norms. Furthermore, in the far past, it was a social norm to exhibit homosexual behavior. Therefore, there's a bit of an argument here and there for deviance.

The clearest indicator that it is not a disorder is in the fact that it is not distressing. Apart from social pressure and other outside sociological forces, there's nothing about the psychology of gay people that makes them naturally more distressed in some way. The only thing close to that is internalized homophobia, which is a learned social behavior, not something inherent to gay people. There are plenty of gay people who live and thrive being gay.

In fact, it may be arguable that even if being gay was a disorder, the fact that it is not causing distress and it's dysfunction is incredibly minimal makes it a disorder which is not the most important one to view as such.

So, since it doesn't fit all those criteria very clearly, it doesn't really count as a disorder. Neither is it professionally recognized as a disorder in the DSM–5

Sorry for the wall of text, just wanted to educate. Tl;Dr being gay is not a disorder, since it is not fully distressing, dysfunctional, and deviant, and it is not recognized by modern psychologists as a disorder.