This is, in my understanding, one of the gay friendly passages. Why? Because it says the ones who are in the wrong are those who forbid marriage. Now Timothy was probably not thinking of gay men and lesbians or any other variation of human sexuality, yet… and yet it is clear. Everything created by God is good and as long as we receive it in thankfulness we are using it correctly.
I’ve heard the arguments that homosexuality is unnatural. I’ve read the psychiatry books that claim it is a diversion of the sexual drive or lack of good parenting or a number of other things. And all of the above fail because they don’t look at what actually happens in nature. In the natural world sex is not just about procreation and homosexuality occurs just as does heterosexuality. While the majority of gendered animals, along with the majority of humans, may not have an interest in same-sex sexualities, the lack of a majority preference doesn’t make something abnormal.
Certainly the writer of this epistle to Timothy had in mind heterosexual marriage. But there is fairly clear evidence that marriages between men happened in the Roman Empire. In fact one of the emperors married another man and that man was taken into the households of several other emperors after the death of his husband. (Caligula and the three emperors in one year) The satires were about the emperor dressing as a subordinate rather than the same-sex marriage. So there was certainly information about same gendered marriages for Timothy to confront if necessary.
While this letter may not clearly give evidence in support of marriage for all people irrespective of the genders of the couple, it still is a warning to those who want to set up barriers between the Christian and celebrating the way they are created.
1 Timothy 4:1-5
 Now the Spirit expressly says that in later times some will renounce the faith by paying attention to deceitful spirits and teachings of demons,  through the hypocrisy of liars whose consciences are seared with a hot iron.  They forbid marriage and demand abstinence from foods, which God created to be received with thanksgiving by those who believe and know the truth.  For everything created by God is good, and nothing is to be rejected, provided it is received with thanksgiving;  for it is sanctified by God's word and by prayer.