Masturbation is mostly performed by men and a little percentage of women also masturbate. This discussion will be based on the medical, physical and mental point of view.
1.It makes the penis or d!ck to get weak when been used in the body of a woman.
2. It can lead to serious mental side effects as it may cause dependence.
3. It is a serious sin in the holy bible.
4. It makes a pen!s to develop too many veins thereby making it unattractive.
5. It causes infections in females.
6. It weaken the hormone responsible in producing sperm.
7. It makes you feel guilty.
8. It makes a man moan, suffer and starve for real sex during the period of masturbating.
9. It reduces the period of ejaculation in men.
10. It can become addictive.
11. It weakens the womb in females-thereby making the womb unable to carry a child which leads to miscarriages most of the time.
12.Sometimes it causes infertility in women.
13. Excessive masturbation may lead to premature ejaculation in men, in other words the male ejaculates just after the sexual intercourse has begun or, in some instances, before it has even begun.
14. It causes cancer in women .
15. It can make a woman lose her virginity.
16. In fewer cases, it can cause sperrm disability which leads to abnormal children.
With this few points i have made, I will take it that masturbation causes harm to human body. So it should be strictly avoided except if only to be used for medical purposes.