Just when you thought you knew everything there was to know about an orgasm, someone is one up on you.

More specifically, "someones" -- four sex researchers who have packed "The Orgasm Answer Guide" with questions you may not even have thought to ask:

1. Are the sensations experienced from orgasm the same for males and females?

This one is tough, but a 1976 experiment did try to compare his-and-her orgasms, asking college students to write descriptions of their climax. When gender-specific words were replaced with gender-neutral words, judges were unable to tell if the person writing the description was male or female.

Among the words used to describe orgasm: lightheadedness, a rush, relief and euphoria. These similar reactions may be due to the penis and clitoris having the same nerve route – a pair of pudendal nerves.

2. At what point in their lives can people experience orgasm?

This is a matter of great debate. Some professionals believe that humans do not orgasm until they hit puberty. Others argue that people can experience orgasm at any point, given that the nerve network involved in sexual response is present and functional even before birth.

3. Is the ability to have orgasms inherited?

Research comparing identical and fraternal twins found that women reported a great deal of variety in the frequency of climax during self-pleasuring or intercourse. The identical twins, however, were more similar than the fraternal twins in the frequency of orgasm. Researchers of the TwinsUK study believe that genetic variation can help to explain the difference.

4. How does nipple stimulation affect orgasm?

For some people, nipple play can impact the chance of reaching climax and/or maximize its intensity. The reason why, it is speculated, is that sensory activity from both the breast and genitals travels to some of the same neurons in the hypothalamus of the brain. Hence, sensations may be heightened when these hot spots are simultaneously stimulated.

5. Can having an orgasm influence a female’s ability to conceive?

Quite possibly. The wave-like contractions of the uterus during orgasm increase the subsequent suction action. This suction draws semen closer to the cervix and uterus.

At the same time, the hormone oxytocin, which is released at climax, stimulates the uterine muscles to contract even more forcefully, further upping the suction produced. So, more sperm enters the uterus.

6. Is erection required for his orgasm?

Many men may find this mind-blowing: Erection is not needed for orgasm (and emission, for that matter). The nerves sending messages from the penis to the brain are active regardless of whether he is hard or soft during stimulation.

7. Can reaching orgasm trigger a heart attack?

"Death in the saddle" is a rare occurrence. The effort put into sexual activity is much more to blame than reaching climax. The fact that 70 percent of these deaths happen during extramarital intercourse suggests that stress may be a factor too.

8. How does a hysterectomy affect orgasm?

The removal of the uterus, and in some cases the cervix with the uterus, can impact a woman’s climax. It can reduce or eliminate pain and menstrual bleeding that can impact her sexual pleasuring.

However, the surgery can damage blood and nerve supplies, impacting sensation in the genitals. Medications and post-surgical trauma can also affect her ability to orgasm.

9. Can Viagra help her reach the "Big O"?

Erectile dysfunction drugs have been tested in women as potential treatments for sexual disorders. While these drugs do increase blood flow to the clitoris, their impact on sexual desire and orgasmic response is still highly controversial.

With sex book shelves packed with reads that are all about orgasm, "The Orgasm Answer Guide" truly stands out in cutting right to the chase, with easy to absorb scientific data to back real claims. While it isn’t exactly erotica, learning about your sexual potential with a solid read can be a turn-on in and of itself.

Dr. Yvonne K. Fulbright is a sex educator, relationship expert, columnist and founder of Sexuality Source Inc. She is the author of several books including, "Touch Me There! A Hands-On Guide to Your Orgasmic Hot Spots."

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