Identical twins have different fingerprints. Let that sink in. They have identical genes and DNA, and yet their bodies are different. Fingerprints are therefore not entirely determined by genes. On the other hand, those twins didn’t learn from society to have different fingerprints.
Neither a ‘nature’ theory (i.e. genes) nor a ‘nurture’ theory (i.e. learning) can adequately explain the difference in fingerprints. There must be something else.
This argument comes up again and again in explaining homosexuality. The nurturist may even believe that gay people choose to be that way, and so they advocate that gays be punished. Uganda and some other countries have made laws putting gays in prison for life, or even giving them the death penalty. In perhaps less extreme America, many people are advocating Gay Conversion Therapy, on the theory that gay behavior, learned from society, can be un-learned as well. Conversion therapy often has disastrous consequence for the victims of such thinking.
On the other hand, almost all gay people will say, “I didn’t choose to be gay; I’ve been that way since birth.” That suggests a ‘nature’ argument. For years, researchers tried to find a ‘gay gene’. At one point, scientists thought that they had identified an Xq28 gene that predicted homosexuality, but that was later proven insignificant.
There is clear evidence that heredity plays some role. One estimate is that one’s genetic make-up constitutes at most 25% of one’s gender identity. But that leaves another 75% attributable to other factors. However, the most recent and comprehensive study of gay genetics (Science magazine, reported by Public Broadcasting Service) concluded that the genetic contribution must be ‘polygenetic’, that is,
“…meaning hundreds or even thousands of genes make tiny contributions to the trait. That pattern is similar to other heritable (but complex) characteristics like height or a proclivity toward trying new things….”
In other words, a combination of genes may increase the probability of a tendency towards some behavior, in the same way that your genes may predict a vulnerability towards a disease like cancer, but the environment is still important in giving you cancer. Some combination of nature and nurture is responsible. Even in these cases, we are still relying on a nature-nurture mindset, only using a linear continuum between the two.
Still, twins’ fingerprints are not a combination of nature and nurture, since the fingerprints are ‘hard-wired’ without any learning in the sense of Pavlov’s dogs or B.F.Skinner’s Walden Two. Similarly, the gay person’s claim that he has been that way from birth suggests that he had no choice in the matter and did not change from straight to gay at any point after a learning experience.
The way to avoid this nature-nurture mindset is to introduce a third determinant of personality: what happens in the womb. Something has clearly happened within the womb to change the twins’ fingerprints. There is nothing revolutionary about this idea; think of crack cocaine babies, whose health is undermined by the mother’s chemistry due to cocaine use.
There are cases where one identical twin is straight and the other gay. Note that each fetus is encased in its own placenta, so there can be differences between the two placenta, such as chemistry, but also position, movement, and other variables. A lot can happen within those nine months of pregnancy, about which we still know very little.
By considering that a lot of behaviors and ‘hard-wired’ characteristics might result from intra-uterus conditions, we can free ourselves from the prison of nature-nurture thinking. We can now consider three contributors to future behavior, rather than just the two.