Impotence and Sterility
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Direct answer
Impotence is the inability to perform the sexual act; sterility is the inability to reproduce. A person may be potent but sterile, or impotent yet fertile, so the two are never interchangeable. Causes are physical — developmental, endocrine, neurological, vascular or local genital disease — or psychological. Assessment needs a full history, general and genital examination, hormonal tests and semen analysis in the male. Medico-legally these questions arise in nullity of marriage, disputed paternity, rape and sexual assault defences, and artificial insemination without consent.
What you must remember
- Definitions: impotence in the male is persistent inability to achieve or maintain erection sufficient for penetration; sterility is inability to beget or conceive children despite potency.
- Male causes: congenital maldevelopment or undescended testes; endocrine disease such as diabetes and hypogonadism; local conditions — phimosis, Peyronie disease, epididymo-orchitis; neurological disease; drugs including alcohol and opioids; and psychological causes, which are common.
- Female causes: developmental anomalies of vagina or uterus, endocrine disorders including polycystic ovarian disease, tubal blockage and chronic pelvic infection; vaginismus prevents intercourse but not fertility.
- Work-up: secondary sexual characters, genital examination, hormone profile including testosterone and prolactin, and semen analysis after two to three days of abstinence — count, motility and morphology; azoospermia proves sterility, but no laboratory test proves impotence.
- Nullity of marriage: impotence existing at the time of marriage and incurable is a ground for annulment; sterility alone is not.
- Criminal cases: an accused in a sexual assault case may plead impotence, and the court directs examination for potency; the doctor assesses on history and examination, never concluding capacity from anatomy alone.
- Artificial insemination: governed by the assisted reproductive technology legislation of 2021; insemination of a woman without her consent, or with donor semen without the husband's consent, is actionable; written informed consent of both spouses is mandatory.
Common confusion
The examiner's favourite trap is the interchangeable use of the terms. A man with normal erections but azoospermia is potent yet sterile; a paraplegic may be impotent yet father a child by assisted reproduction. Equally, no test proves potency — it is a functional conclusion drawn from history, often with court-directed examination.
Exam-focused takeaway
Examiners ask the difference with examples, the causes and work-up of impotence, interpretation of a semen report, the ground for annulment, and the rules on artificial insemination. MCQs test that impotence, not sterility, annuls a marriage, and the abstinence requirement for semen analysis. In viva, describe examining an accused pleading impotence and counselling a couple seeking assisted reproduction.
Frequently asked questions
What is the difference between impotence and sterility?
Impotence is inability to perform intercourse; sterility is inability to beget or conceive children — a person may be potent but sterile, or impotent yet fertile.
Which is a ground for annulment of marriage?
Incurable impotence existing at the time of marriage; sterility alone is generally not a ground for nullity or divorce.
How is male potency assessed?
By detailed sexual and medical history, general and genital examination, and endocrine or vascular tests as indicated; no single laboratory test proves potency.
What makes a semen analysis reliable?
A sample given after two to three days of abstinence, examined within an hour, with at least two samples weeks apart assessing volume, count, motility and morphology.
What is vaginismus?
Involuntary spasm of vaginal muscles preventing intercourse despite normal anatomy and fertility — a psychological cause of female impotence.
When does artificial insemination become a legal problem?
When done without the informed written consent of the woman or her husband, or outside the statutory requirements, it becomes actionable in family law.