Erectile dysfunction (sexual weakness) is the inability to achieve or maintain an erection firm enough for sexual intercourse.
Sexual weakness is often used to refer to erectile dysfunction (ED) in men.

Sexual dysfunction can be broadly grouped into four main categories:
The first is desire disorders, which involve a lack of sexual desire or interest. Second, arousal disorders describe difficulty becoming physically aroused or excited during sexual activity.

The third category, orgasm disorders, includes situations where there is a delay in reaching orgasm or it doesn’t occur at all. Finally, pain disorders involve experiencing pain during sexual intercourse.

Causes of sexual weakness or premature ejaculation:
Sexual weakness, premature ejaculation and erectile dysfunction is especially among people that suffer from anxiety disorders.

There are many factors which causes premature ejaculation, sexual weakness and sexual dysfunction among men and almost 70% of these result from physical or emotional causes.

Interpersonal or psychological problems (Emotional factors): which includes sexual fears or guilt, depression, sexual disorders and past sexual trauma. Anxiety can cause erectile dysfunction in men without psychiatric problems.
Excessive use of drugs: (alcohol, nicotine, narcotics, stimulants, antihypertensives, antihistamines, and some psychotherapeutic drugs) are the main physical factors that can lead to sexual dysfunctions among men.
One of the underlying cause of sexual weakness and dysfunction among both gender can also be pelvic floor dysfunction, etc.
Hormonal deficiencies, heart and lungs disorder, narrowing of blood vessels, diabetic neuropathy, obesity and metabolic syndrome can also be some of the key factors for sexual dysfunction in both men and women.