Yes! It is considered a sin if done out of the wedlock. All the religions sanction monogamous heterosexual relationships, while most of them prohibit adultery (voluntary sexual intercourse between a married person and a partner other than the lawful spouse), premarital sex, prostitution, homosexuality, incest (sexual intercourse between two persons who are too closely related to marry) and bestiality (sexual relation between a human and animal).

For a married couple, sex and reproduction are considered the holiest of acts, which, if done out of marriage, becomes a sinful act.

Let’s talk about Hinduism first. A Hindu must refrain from a sexual relationship till the time he is married. One should practice chastity and remain a virgin till the marriage, especially a girl. However, the ancient temples at Khajuraho and Ajanta & Ellora have provocative imagery carved on the walls evincing sexual activity openly. It also has group sex carvings. Guess, sex was considered a holy act in that era and not as complex and restrained as today. Kama Sutra owes its origin from our land.

The Hindu God, Lord Krishna, is said to have 16,108 wives. In Mahabharat, Draupadi had five husbands. She freely tied the knot with the five Panadava brothers. In Ramayan, Ram’s father, Dashrath, had three wives. These are lucid examples of polygamy practiced in the ancient time. But today, it’s a crime in India. The only exception is in Islam, wherein a Muslim man is allowed to have more than one wife provided he gives both or all of them equal respect, love and status.

A friend from school, who is extremely religious, had once told me that according to Quran, if one commits adultery he/she is severely punished by God. Pre-marital sex is also considered sinful, but less severe. However, anal sex, whether between a married couple or not, and homosexuality is completely proscribed. She suddenly remembered that she was not supposed to even talk about all this because she was fasting amidst the holy month of Ramzan and said that even such thoughts linger in the mind, one is supposed to shoo them away lest it breaks the roza. She ended the discussion then and there.

Islam also allows marriage between cousins. Sometimes, this results in inbreeding which leads to birth defects due to augmentation in the level of some hormones.

In Buddhism, details regarding accepted or prohibited sexual behavior is not specifically mentioned in any of the religious scriptures. However, the Monks and Nuns are supposed to refrain from all sexual activities.

For past many years, Unitarian Universalists are seen to have supported same-sex marriage. Elton John got married to his male partner a couple of years back Unitarian Universalism advocates freedom for people to choose which sexual acts are morally and personally permissible, and to express one's sexual orientation and gender openly.

Times are changing and so are we. We have witnessed a metamorphosis in everything with the changing times. And this might reform our old religious practices and beliefs.