As far as I know, Buddhism is the most observant believers, other than Muslim.  The true Buddhist forbids killing, steal, wanton/licentious/obscene, lies, drink wine/liquor, five so called commandments.

1. Killing -- not only killing human, animals or any living organisms intentionally or unintentionally, it also includes saying things that kill others' confidence, self-esteem, believe, ..., any word/speeches or actions that bring negative effect toward others... etc.

2. Stealing -- taking or possess anything that do not belongs to oneself, whether intentionally or unintentionally, example a pen, that normally will automatically goes into our pocket or bag unintentionally.

3. Wanton/licentious/obscene -- sexually conduct with the wrong person, for example not legally married opposite sex.  Not only non-marriage couples, even legally married couples are not suppose to make love in the day time, at the wrong place for example forest, living room, walkway, bathroom,..etc. The right place and the only place is bed.  In the view of Buddhism, the cause of homosexuality is related to one's constitution as well as from psychological conditions.  From a religious viewpoints, homosexuality cannot escape the item: contradicting morality -- having abnormal sex.  However, from the Buddhist point of view of cause and effect, all worldly sexual desire among men and women, men and men, and women and women contain cause and conditions.  The value of the Buddha's teaching is that the Buddhas and bodhisattvas understand causality very well.

4. Lies -- telling lies, saying thing that is not true.  Other than our daily conversation and salepersons' promotion lines, there are also misleading and fault report in the news media, giving negative effect toward the innocence.

5. Drink wine/liquor -- drinking and get drunk causing inappropriate speeches and actions, for example saying words that hurts other,  quarrel, sexually misconduct...etc.

As a general, Buddhism teaches the existence of passed and next lifes, cause and effect, negative action give negative karma and bring unforturnate consequences to current or future lifes.  These could explain why there are people borned to be unfortunate and some are borned with all the welfare that they could get.  Life is always fair and equal. in Buddhism, there is always an explaination toward any circumstances.