Your question is too vague asking about religion in general. That is like asking are governments allowed to kill people? Depends which one (and if they have military and death penalty). Some religions allow, some forbid. If you are referring to Christian denominations, as you may have been, all regard as wrong, but not all will judge you based on that. The Christian scripture, however, read textually rather than as a living document to use the words of judicial interpretation, is very clear on what it thinks about premarital sex.
Relationship whether to another being or to the Supreme Being (God), is and always will be on the basis of Trust, Faith and Obedience. In the absence of either there is no true commitment and no relationship. With regard to the question at hand .... The answer is obviously NO. It is no because it has always been no.
Despite or regardless I should say of external outward views, God does not alter right and wrong under the feels good do it rules of man. In fact there are extreme consequences for ignoring this mandate, many of which you suffer not only at the present time, but long after your error. The majority of mankind doesn't even bother to look for God, subsequently they go through life unaware of the consequence for which their actions will bring. This does not mean they will not be held accountable though ..... It just means by the time they find out they've BEEN held accountable .... It will be too late!
Some religious leaders and people of faith argue that sexual activity outside of traditional marriage can be spiritually fulfilling. Judaism has a lot to say about sexuality; in the Jewish tradition sexuality is an important path to self-fulfillment, provided it is explored in a faithful and healthy relationship. Procreation is not the sole purpose of sexual intimacy.
Some people (like christians) debate about whether homosexuals should we allowed to worship in a church as in the bible jesus says "no man should love another man the way he loves a woman" and vice versa. I believe that they should be able to worship in a church as it is their choice and if they want to be gay then they can be gay. But this doesn't mean that I am comfortable with the whole concept. I am not a homophobic but I believe that there are two genders for a reason. I think that many people would not "come out the closet" because they want to remain faithful to their God.
Premarital sex is referred to in the Bible as fornication which is a sexual immorality along with homosexuality, adultery, bestiality and incest. The Bible forbids it because when a couple have sexual intercourse, they become one. This is only supposed to be done in a marriage. And besides, the more people you have sex with, the more likley you are to catch STD's.
Premarital sex is a sin, but it is not an unforgivable sin. If you repent, God will forgive you.