In psychology and psychiatry, a condition is considered pathological when it results in behaviours or states of mind which are harmful to oneself and/or others.
Sometimes it is a question of degree. All of us, for example, have little insignificant rituals, or irrational beliefs, or acts of superstition that serve no purpose but are harmless enough. When these come to dominate somebody's life and seriously interfere with normal everyday functioning, they are deemed a disorder, specifically Obsessive Compulsive Disorder (OCD).
We all generally keep objects that only occupy space without any use or function, but it is only when the house becomes a suffocating repository of towering piles of junk and old newspapers that this behaviour is called "hoarding" and treated as a disease.
So, it is the consequences that signal pathology.
Paedophilia is considered an illness because it is believed that children and young people under the age of consent will be harmed by sexual relationships, especially with adults.
Incidentally, the very fact that the age of consent, even in the Western world alone, varies considerably and can be as low as 13 in Spain and as high as 18 in the USA shows how unclear and uncertain many of our notions about sex ethics are.
Therefore, so the current consensus goes, paedophilia is an abnormality and homosexuality, for example, is not purely because of the consequences, harmful in the former and innocuous in the latter.
This is the received wisdom, the present-day orthodoxy and dogma which, interestingly enough, is very different from that of not just 100, or 50, but even a few years ago, when same-sex marriage, for instance, was still generally regarded as, well, queer.
So, if we think that our ideas were so terribly wrong then, they might as well be wrong now, and maybe in a decade or two from today they will have changed all over again, in the same or in the opposite direction.
"Homosexuality" can refer to two things: homosexual tendency and homosexual behaviour. As in many other cases in psychology and psychiatry, it is the acting on the tendency, namely the behaviour, that can more appropriately be considered pathological or not.
If we look at homosexual behaviour in men, we see persons who are prepared to take extraordinary, lethal health risks in order to satisfy their tendency.
Male homosexuals are at very high risk of contracting the AIDS virus and other sexually transmitted diseases, disproportionately high in comparison to the heterosexual population:
The Centers for Disease Control and Prevention (CDC) of the U.S. Department of Health and Human Services published in 2010 a study conducted in 21 American cities, showing that one in five MSM (men who have sex with men) had HIV...The often-repeated wishful thinking "panacea" of the use of condom is just that, a wishful thinking myth.
A coincidence, you say? No, the way HIV, the AIDS virus, spreads has a lot to do with homosexual behaviour.
Before looking into the evidence of brain, genes or hormones we need to recognise that the male body is not designed to be penetrated during sexual intercourse. The lining of the anus is much thinner than the vagina and tears very easily. The lining of the anus, compared to the lining of the vagina, is also designed for nutrients to pass through it - where a healthy vagina will stop sperm entering any part of the body except the reproductive system the anus will allow semen (and any disease it carries) into the blood stream. Also the anal sphincter muscle is designed to expel not accept objects which can lead to problems in later life...This is from the website of the U.S. Food and Drug Administration (FDA), a federal government agency:
So biologically the male and female bodies are compatible with each other not bodies of the same gender.
The Surgeon General (C. Everett Koop, Surgeon General 1982-1989) has said, "Condoms provide some protection, but anal intercourse is simply too dangerous to practice".
Condoms may be more likely to break during anal intercourse than during other types of sex because of the greater amount of friction and other stresses involved.
Even if the condom doesn't break, anal intercourse is very risky because it can cause tissue in the rectum to tear and bleed. These tears allow disease germs to pass more easily from one partner to the other.
Male homosexual behaviour may reduce life expectancy up to 3 times more than smoking. This is what "Modelling the impact of HIV disease on mortality in gay and bisexual men", a peer-reviewed study published in the Oxford Journal of Epidemiology, says:
In a major Canadian centre, life expectancy at age 20 years for gay and bisexual men is 8 to 20 years less than for all men [for smokers is 7 years less]. If the same pattern of mortality were to continue, we estimate that nearly half of gay and bisexual men currently aged 20 years will not reach their 65th birthday. Under even the most liberal assumptions, gay and bisexual men in this urban centre are now experiencing a life expectancy similar to that experienced by all men in Canada in the year 1871.Are men engaging in sex with other men only harming themselves, although that in itself would be sufficient to recognize this behaviour as psychologically pathological?
Actually no, the risk spreads to society at large. Tuberculosis is increasing in the world, "and 'the worldwide number of new cases (more than 9 million) is higher than at any other time in history' largely, as the authoritative medical journal The Lancet explains, thanks to the spread of HIV: 'Due to the devastating effect of HIV on susceptibility to tuberculosis'."
All this shows that male homosexual behaviour has consequences that, if political correctness and fears of being ostracized as a "homophobe" - things that have nothing to do with medical or psychological considerations - did not stand in the way, would rightly make it classified as pathological.