The risk of dying
Everyone realizes having sex before marriage can have dangerous consequences. Even condoms避孕套 and other 'safe sex' devices, there is still a chance of pregnancy懷孕. If sperm精子, which are living cells, can make it through these devices, how much easier is it for a virus (many times smaller than a human cell) to bypass the device. More than 600,000 cases of AIDS have been reported in the United States since 1981, and as many as 900,000 Americans may be infected with HIV. Numbers in other parts of the world are even higher.

Risks of disease or infertility
Many incurable diseases, some that will make both men and women infertile are spread through sexual relationships. Once again 'safe' sex does not offer 100% protection from these diseases. These diseases are often termed STDs (Sexually Transmitted Diseases) Herpes and other STDs are everywhere. (Over 50 million cases of Herpes in the U.S. alone.) Why risk contracting an STD? A Doctor I know suggested that within the next few years over 1/3 of the female population will be infertile不孕 due to sexually transmitted dieseases.

The risk of damaged or lost relationships
We are emotionally wired to see sex as a commitment. When a casual sex relationship ends, you and the other person experience guilt and pain of the unspoken promises that were broken. I have seen many people lose good friends after having sex, because boundaries were crossed that no makes their friendship awkward.

The risk of depression
Pre Marital sex is almost a form of abuse, as the partners are using each other without making the commitment of life long trust and love. This often causes emotional damage that may lead to an increased chance of mental depression and emotional despair.

The risk of damaging your future marriage
I have several friends who are married, or who are about to be married that have struggled greatly with telling, or learning about, previous sexual encounters. This knowledge causes stress on these relationships because of lack of trust and regret.

The risk of sexual dysfunction官能障礙
Every year people spend millions of dollars to correct sexual dysfunction through drugs and psychotherapy. Many people think that once they enter marriage the problems of sleeping around, pornography, and masturbation will stop. However, many find these problems to be more noticeable and controlling once they are in a marriage. I have spoken with several good Christians who have dysfunction because of a current addiction to pornography. Side note: Romance novels are women's pornography and can often cause just as much trouble in a marriage as the woman is expecting unrealistic romance.