Let's take a look at what happens to our bodies when we drink alcohol.
Alcohol is a central nervous system depressant. Alcohol acts by inhibiting parts of the central nervous system important for sexual arousal and orgasm -- respiration, circulation and sensitivity of nerve endings.
Alcohol dehydrates the body. Sexual arousal needs a certain amount of blood to bring oxygen and greater sensation to the genitals.
Alcohol can make getting an erection more difficult. Large amounts of alcohol (or long-term) consumption has been associated with problems getting erections. Dehydration with drinking causes less blood volume and a rise in angiotensin, the hormone associated with erectile dysfunction. Alcohol's inhibition of the central nervous system also contributes to the problem.
Alcohol can cause vaginal dryness. The dehydration common when drinking alcohol can contribute to fatigue, headaches and vaginal dryness.
Alcohol can delay or prevent orgasm. In 2004, a study found 11% of alcohol users were likely to have problems reaching orgasm. The men had difficulty ejaculating while the women needed much more stimulation to have an orgasm than women who had little or nothing to drink.