Genetic Explanations, Liberty, Politics and Economics, Religion

Why homosexuality is natural – an evolutionary explanation

Since Aristotle, we have philosophised a scientific and moral order to the world.  A “natural order” or “utopia” to creation.  A way things were meant to be.  If we acted against this order then nature would be disrupted and chaos would ensue.  This pre-supposition was incorporated into the major religions where it is assumed that God had a plan for creation and that His plan was “designed” to be harmonious.  If we could only understand what God intended for the world then we would know how to behave. But only religion knew how we ought to behave according to God’s design, because only religion knew God’s mind. Religion therefore got involved with “moral teaching”, which was a code of behaviour that God had intended and endorsed.

So religion expropriated moral behaviour based on a belief in a “purpose” or “design” of nature.  Men were men, and women were women, and they were meant to marry and have children.

However, unlike Aristotle’s assertion and accepted religious doctrine, evolution does not provide an “ought” for nature.   There is no intention in evolution.  Genes have no intelligence or sentience.  They are inert, self-replicating, complex molecules that have evolved over 3,500,000,000 years to build intricate life-support machines around them (living organisms) that help them replicate themselves.  We humans are a disposable container to further the interest of our genes.  We die, they don’t.

Evolution works by natural selection.  Each generation of genes has small random variations and mutations (some beneficial, most harmful) from which nature chooses the best characteristics using natural selection.  The beneficial behaviours survive and are amplified in future generations and the unbeneficial behaviours dwindle or die out.

Genes merely cover their options by providing random variation to ensure that whatever the future environment may be, some of them will be adapted to take advantage of it.

Without this evolution could not occur and we would still be living primordial slime.

So massive climate change, asteroid attacks, disease and any number of previous natural disasters has not wiped out life on our planet.  It just changes which genes (and therefore which species) are best adapted for the new environment.

So there is no “ought” in evolution.  There is no “intent” or a way things were meant to be.

So nature naturally provides variation in human characteristics and behaviour.  We have variations in skin colour, variations in hair colour, variations in aggressive behaviour and variations in intelligence.  And yes, variations in sexuality.  Some people are gay, some are heterosexual, and some can be anywhere on the spectrum in between.  So homosexuality is as natural as red hair or black skin or blue eyes.

Studies have shown that homosexuality runs in families, leading most researchers to presume a genetic underpinning of sexual preference. However, no major gene for homosexuality has yet been found.   But whilst much variation is directly caused by genes, we know that some variation is only indirectly caused by genes.  Recent studies in epigenetics have found a plausible mechanism for human homosexuality.  Epi-marks constitute an extra layer of information attached to our genes’ backbones that regulates their expression. While genes hold the instructions, epi-marks direct how those instructions are carried out – when, where and how much a gene is expressed during development.

Sex-specific epi-marks produced in early fetal development protect each sex from the substantial natural variation in testosterone that occurs during later fetal development. Sex-specific epi-marks stop girl fetuses from being masculinised when they experience atypically high testosterone and vice versa for boy fetuses. Different epi-marks protect different sex-specific traits from being masculinised or feminised – some affect the genitals, others sexual identity, and yet others affect sexual partner preference.

Epi-marks are usually erased and produced anew each generation, but recent evidence demonstrates that they sometimes carry over between generations and thus can contribute to similarity among relatives, resembling the effect of shared genes.  When sex-specific epi-marks are transmitted across generations from fathers to daughters or mothers to sons, they may cause reversed effects, such as the feminisation of some traits in sons and similarly a partial masculinisation of daughters.

So this mechanism can affect a developing foetus’ response to hormones in the womb which may affect brain development and sexuality.  But how can a genetic trait that causes sexual preferences which will not result in pregnancy and children survive generation after generation?   The reason that many people think homosexuality is “unnatural” is because it denotes behaviour which does not result in any future generations.  Natural selection should ensure that genes for homosexuality will die out.  Many believe the fear of persecution caused many homosexuals to marry and have children in order to fit into society, thus propagating these genes into future generations.  However,  mathematical modeling demonstrates that genes coding for these epi-marks can easily spread in the population because they only rarely escape erasure causing homosexuality in the offspring.  Genetic transmission of epi-marks between generations is the most plausible evolutionary mechanism of the phenomenon of human homosexuality.

So our knowledge that homosexuality has a genetic basis, which is subject to evolution by natural selection, would lead us to predict that homosexuality would be rare.  This is verified by the  results of the third National Survey of Sexual Attitudes and Lifestyles recently published in The Lancet.   It shows that 7% of men have had some sort of same-sex “sexual experience” and only 4% had physical sex with a man.  The percentage of females who say they have had a sexual “experience”, including kissing, with another woman was 16% and the number admitting to having sex with another woman was 8%.  However there are good evolutionary reasons why we would predict that homosexual behaviour in women would be greater than in men.  (See blog:  Is there a bit of lesbianism in all women? )

Now that homosexuality is accepted in modern societies there is less pressure on homosexuals to marry and have children in order to “fit in” and avoid persecution.  This could mean that there will be less homosexuality in the future because if there are genes which code for homosexual behaviour they would become even less common.  However the recent research into epi-marks suggests that homosexuality will never disappear.  It will just remain rare.

Gay Marriage and Liberty

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Genetic Explanations, Liberty, Religion

From where do we get our moral behaviour?

Since Aristotle, we have philosophised a scientific and moral order to the world.  A “natural order” or  “utopia” to creation.  A way things were meant to be.  If we acted against this order then nature would be disrupted and chaos would ensue.  This pre-supposition was incorporated into the major religions where it is assumed that God had a plan for creation and that plan was “designed” to be harmonious.  If we could only understand what He intended for the world then we would know how to behave. But only religion knew how we ought to behave according to God’s design, because only religion knew God’s mind. Religion therefore got involved with “moral teaching”, which was a code of behaviour that God had intended and endorsed.

It was consequently assumed that if we did not believe in God then our moral behaviour could not be guaranteed.   If we don’t believe in God what is to stop us murdering and raping?  If there is no retribution after death what is to ensure we live a good life?  Non- religious people were feared, excluded, subjected to violence and sometimes death.  Religious belief was considered the default position.  The term “atheist” is a strange word construct that confirms this thinking.  We are not normally described as something we are not.  We are not non-socialists, or non-Manchester United supporters.  Only non-believers.  In past times atheists would have been advised to play the game, go to church and pretend to believe in order to avoid persecution.

So religion expropriated moral behaviour.

But mankind is moral and ethical in the absence of religious belief.  There is no evidence that religious people are more moral than atheists. Or that they are more law abiding. In recent polls, 65% of British people said they weren’t religious and weekly church attendance in the UK is down to less than 2%.  No massive crime wave has ensued.  Violent crime is at a 30 year low.

So if it not religion, where do our morals come from?

Interestingly there are a number of psychological tests which can elucidate our moral compass i.e. establish what moral beliefs we all hold.  These tests can be applied to people from all different cultures and belief systems.  From these tests we can demonstrate that mankind shares an innate moral code, independent of religious indoctrination or cultural teaching.  This moral code is hardwired in the same way as much animal behaviour is hardwired.  It is part of human nature.

Most humans would feel bad about causing harm to another person. We would generally feel revulsion at seeing a child raped or an innocent murdered.  We feel compassion towards small, vulnerable children.  We look after our sick and dying.  We evolved as an emotional, social, altruistic species (but who admittedly can turn violent if threatened).  These behaviours of nurture, collaboration, teamwork, empathy and compassion have led to our success as a species.  Altruism works in evolutionary terms if an individual of a species has a reasonable chance of it being reciprocated.  This is the “is” of human nature.

However, unlike Aristotle’s assertion and accepted religious doctrine, evolution does no provide an “ought” to human behaviour.   There is no intention in evolution.  The Universe was not meant to be a certain way.  There are just random behaviours encoded by our genes that lead to us to be more or less successful in propagating our genes into the next generation.

Evolution occurs by the process of natural selection.  The beneficial behaviours survive and are amplified in future generations and the unbeneficial behaviours die out.

So it seems that our moral code actually has a Darwinist origin, not a religious origin!

Combine this force of nature with our intelligence as a species and our ability to learn, anticipate and interpret our environment and we have very complex “human” behaviour (a “culture”), which in developed countries now includes evidence based debate, democracy and the rule of law.  This is where we must derive our “ought” of human behaviour i.e. how we should behave.

If we combine our innate moral code with rational, evidence based debate, democracy and the rule of law we have a functioning society. A “civilization” that can even accommodate a few immoral miscreants that the variation component of the mechanism of evolution by natural selection throws up. Our intelligence as a species has allowed us to plan and control our own society.  Most of us have the ability to see how things would be if we allowed anarchy to predominate, so we work hard to create order, security and welfare.

So, we have an inbuilt, genetic, emotional behavioural code and a derived behavioural code from our experience and interaction with our environment.  Some things just feel wrong. Some things we rationalise as wrong.  Some of these emotional and rational codes we choose to call “morals”.

Religion was once beneficial.  It was a good way of creating social control through its teaching and threats of social exclusion and eternal damnation for those that misbehaved.  But now we have the ability to collect real evidence through scientific methods for our evidence-based debates.  We now have good-enough democracy and adequate rule of law.  We have superseded religion.

The negatives of religion are now outweighing the positives:  Illogical, irrational thinking; superstition; religious discrimination; the sinister underpinnings of Islamic Jihad and the barbaric treatment of women are all part of the same belief system.  The same irrational belief system underpins extreme Islam and the benign Church of England. If we condone one version, we must condone them all.  We can no longer claim that we should believe in an untruth (religion) because it is beneficial.  The balance has changed.  We must now free ourselves from the shackles of religious indoctrination.  As Steven Weinburg famously said, “with or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion.”

We are right to challenge religious beliefs in order to create a better, more moral, more rational, fairer and more equal world.

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