The majority of the gay population are into anal sex. According to Gregory Underwood, author of Gay Men and Anal Eroticism, states "that 3/4 of gay men have had anal sex at one time or another. Assuming that these men continue to have anal sex that leaves a quarter of gay men that neither have tried it or they no longer have anal sex. So, why is that? What are the basic possible reasons some gay men don't have anal sex or don't like having anal sex?
There could be several reasons this happens:
Personal Taste. While some guys may have tied anal, and discover that they find little or no pleasure in topping and/or bottom. For some gay men this will most likely happen after their "first bad experience", and some have just never tired anal sex and have no desire to participate, either by choice, anxiety or stigma.
Stigma. In our general society there is a stigma associated with men who have anal sex with other men. A top is generally thought to be the dominant, while the bottom is considered more submissive; this isn't always true. This could cause a problem with let's say a bottom who doesn't want to be perceived as the "weaker" or "less dominate" man. Then there is the view that a bottom in society commonly seen as the "female" role in the relationship.
Anxiety. The risk of contracting an STI, from most that can be treated to those that are incurable, this causes quite a bit of anxiety. Anal sex can lead to several fears; so for many this leads to just abstaining from anal sex. For many they will prefer non-penetrative sex as a substitute.
Feelings. Anal sex is considered one of our closest physical connections. Form many there are feelings associated with that level of closeness. Many gay men will abstain from anal sex unless there is an emotion connection with their partner. The emotional physical connection is to some the best way to enjoy and experience anal sex; this may lead to barebacking or anal sex without a condom.
Regardless of what some reason may be, we have to conclude that sex is very personal, and will vary by preferences, pleasures, wants and needs, and desires.
It's important to understand that there is nothing wrong with not being into anal sex. For many gay men they appear happy to live their lives without ever experiencing anal intercourse. Anal sex can be replaced by non-penetrative sex like frottage or intercrural sex. Then again there is oral sex and many other sexual fetishes that do not involve anal penetration. It's about feeling an emotional bond, and having fun with your sexual partner.