Did God create just XX and XY?

Thanks to science teacher Ronan Franco both for the suggestion and part of the references.

Doesn’t matter what you think about if God exists or not, neither what God is this, to effect of argument, in this text we will use the hypothesis that God exists, and He is the god described in Christian Bible, responsible for universe’s, earth’s, nature’s, man’s and woman’s creation (Genesis 1:1-1-28), He created the light, the shadows, the peace and the evil (Isaiah 45:7), that is, the god who created us in the way we are, and whom will we should to obey (John, 6:38), and whose will is superior than our.

Whit all this in mind, as biologist I may analyze the nature and understand it as God creates it, don’t according my own will, therefore, it is strange when some Christians say “God just create XX and XY” talking about sexual chromosomes, like Brazilian congressman Eduardo Bolsonaro (who is in the opening photo with a card in which is written in Portuguese: “There is only XX and XY”); ok, it could be just unknown and don’t bad will about God’s Creation, thus, we will speak a little about what Biology knows about this Creation.

As who assisted high school knows, our physical characteristics are contained in our DNA, which is a “recipe” of our body structure. The DNA is an extreme long molecule, composed of the repetition of four nucleotides (adenine, thiamine, guanine, and cytosine) which alternate each other. In the eukaryotes (living beings with cell nucleus), the DNA is found in a semi organized way instead the cell nucleus, enrolled in proteins called histones, forming little blocks called chromosomes. Humans generally have 23 pairs of chromosomes (see the image below), being the last two called “sexual chromosomes” or “XY pair”. They have not only genes kinked to sexual characteristics, but also genes liked to vision, blood coagulation, example, although, generally your sex is defined for this pair.

Human chromosome pairs

About sex definition, however, the XX/XY isn’t valid for all animal kingdom, although it is common in many dioecious species (that is, species in which sexes are separates in two different beings), being the rule that females present two X chromosomes (XX), and males present one X and one Y chromosome (XY), as in humans. In general mammals, the default condition is the female, being the male sex determination determinate for a specific gene called SRY (Sex-Determining Region Y)¹, localized in Y chromosome. However, there are animal species which have not the Y chromosome; in those males have just one X chromosome and females have two X chromosomes¹. Other animal species present what is called “ZW system”, where males and females have different combinations, as mammals, nevertheless are females which have a different pair (ZW) while males have the pair ZZ¹. Ok, I know when people say God create just XX and XY are talking about human beings but not the rest of God’s Creation.

Indeed, statistically the majority of human beings present XX or XY pairs, and their phenotype is expressed as female or male, successively, however, yet this pair sometimes presents anomalies which, as we have said in the first paragraph, are made for God’s Will, so they need to be respected. The first is the hermaphroditism, which is divided in true hermaphroditism (when the child burns with both male and female organs formed), female pseudo hermaphroditism (women with normal ovarian tissue, but with external sexual organ either bad formed or masculine), and male pseudo hermaphroditism (men with feminine external organ or incomplete); in all these cases the XY genotype can be present, however the sexual phenotype isn’t the statistically patronized².

Nonetheless, God don’t create just hermaphrodites with XX/XY pairs, God experimented and create so diversity in sexual chromosomes that a least one in each thousand people has some kind of alteration². Between the alterations created by God we have the X0, known as Turner’s Syndrome, in which people has just one X chromosome (estimated 1 in 2,500 births ⁹)³; we also have the Klinefelter’s Syndrome, where the pairs aren’t pairs, variating between XXY, XXYY, XXXY, XXXYY, XXXXY (estimated 1 in 500 births of boys and 1 in 50.000 births of girls)⁴; the Jacobs’ Syndrome, where the pair is really a trio XYY⁵ (estimated 1 in 1,000 births); the polysemy of X chromosome (XXX or XXXX) (estimated 1 in 1,000 births)⁶; the Morris’ Syndrome, which consists of women who born with XY pair (estimated 1 in 25,000 births)⁷; and the De la Chapelle’s Syndrome, which consists of men who born with XX pair (estimated of 1 in 20,000 births)⁸ (see infographic below).

That is, God not did more than just XX and XY determining men and women, but also determined that at least one in thousand women and one in 500 men born with something different than this; if God created in this way, who are we to criticize, isn’t it? Besides this, it is increasingly clear that there is genetic influence (don’t confound with genetic determination) or epigenetic influence (epigenetic herd is the transmission of experiences occurred with the parents to children, which don’t occur through DNA) in sexual orientation¹⁰, that is, although we don’t know a “gay gene” (albeit XQ28 region, at the tip of ,X chromosome, which contains several genes, be a strong candidate¹⁷, with strong indications that everybody would have the ‘gay gene’, but it just would manifest itself if a methyl group was linked to specific regions of DNA¹⁹) interactions between various genes and the environment (environment shouldn’t be understood as ‘parents rearing’, nor ‘play with dolls’, but chemical interactions)¹⁸ can prevail the tendency to certain sexual preference (both heterosexual or homosexual), which isn’t individual choice, in the same way that eye color, high or predisposal to heart diseases. Why did God decide to do in this way? Well, maybe we could not explain, after all, the designs of God are mysterious, but science knows that between 2% and 6% of all human population is naturally homosexual, and recent researches²⁰ about homosexuality prevalence even if “excretory organ doesn’t reproduce” (as said recently a Brazilian Christian politician in a debate to the presidency of the republic). The researches indicate that, even don’t reproducing, homosexual people would be important in maintenance and rearing of children of their heterosexual relatives, which don’t carry on an advantage for the individual, but for the species, in the same way, example, that naked mole-rats communities, where not all individuals reproduce, which is good for the group. Likewise, transgender and transsexuality aren’t just social, which can be force redefined nor for personal choice, instead, science have shown that those people probably were born in this way, and that culture served them only in the way they identify themselves¹¹. “Ok,” maybe you say. “But god forbid homosexuality, it is in the Bible!” Yes, it’s true, God forbid it, example, in Leviticus 18:22, but in the same chapter God forbid the sex with woman in her period and I don’t see manifestations against men who disobey it; moreover, in the next chapter (19:13), God order don’t overwhelm your neighbor. The fact is that society changes, and maybe God’s planes for us wouldn’t be the same that He had for the Israel sons 3 thousand years ago…

Returning, I’ve talked about XY chromosomes don’t be exactly as we thought in relation to human species; am I talking that there are no differences between men and women as Postmodernists say, example? Of course I’m not talking that! There are many physical behavioral and neurobiological differences between men and women, such as in parental care, psychological, aggressiveness, development and work of brain, physical strength, dominance, and many others¹², which aren’t just social constructions, that is, both definition of sex and its characteristics and sexual identity aren’t socially defined, but in reverse, a big part of our society was determined by this¹². It happens that all differences are averages, that is, of course there are women who are stronger, taller, or more aggressive than many men, but in the average men are stronger, taller and more aggressive than women. By the way, that is a point on which, amazingly, Conservative Christian right and Postmodern left agree and are together in the attack to science: for both don’t exist biological pre-skills, in a clear example of Horseshoe Theory proposed by Faye¹³, according who political extremes aren’t distant as in a line, but they approach each other, like horseshoe tips¹⁴.

The fact is that both sexual determination and sexual identity and orientation are much more complex than seem at first glance¹⁵, and even though most of us are men and women with XY and XX chromosomes, respectively, the fact is that there are much more diversity than this when we get all humanity, and there are gray areas in which we can’t define easily a person in this binary structure. Nonetheless, few legal systems englobe something beyond the binary when it provides legal rights and social status¹⁵. By the way, the study of Ainsworth published in Nature¹⁵ is a very interesting thing to read, because it put together recent science discoveries with theories of humanities¹⁶.

With all the above, both as biologist and human being who appreciate God’s creation and try to understand it, I submit myself to the will of God about human diversity, and I think that who are fight against are confounding their own will and preconceptions with God’s will.

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1 - MARCEL, G. Sistema de determinação do sexo: XY, X0 e ZW. In: Eu quero biologia, ago 18, 2014. Available at [http://www.euquerobiologia.com.br/2014/08/sistema-de-determinacao-do-sexo-xy-x0-e.html]; access in ago 9, 2017.

2 – MIRANDA, D. Os distúrbios dos cromossomos sexuais: provocam infertilidade ou desenvolvimento anormal Síndrome de Klinefelter: 47,xxy Síndrome de Turner: 45,x. Available at [http://slideplayer.com.br/slide/4293054/]; access in ago 9, 2017.

3 – SKUSE, D.H.; JAMES, R.S.; BISHOP D.V.; COPPIN B.; DALTON P.; AAMODT-LEEPER G.; BACARESE-HAMILTON M.; CRESWELL C.; MCGURK R.; JACOBS P.A. Evidence from Turner's syndrome of an imprinted X-linked locus affecting cognitive function. In: Nature, jun 12, 1997. Available at [https://www.ncbi.nlm.nih.gov/pubmed/9192895]; access in ago 9, 2017.

4 – KLINEFELTER Syndrome. In: Eunice Kennedy Shriver National Institute of Child Healt and Human Development. Available at [https://www.nichd.nih.gov/health/topics/klinefelter/Pages/default.aspx]; access in ago 9, 2017.

5 – 47,XYY Syndrome. In: Genetics Home Reference. Available at [https://ghr.nlm.nih.gov/condition/47xyy-syndrome]; acesso em 09 ago 2017.

6 – Triple X syndrome. In: Mayo Clinic. Available at [http://www.mayoclinic.org/diseases-conditions/triple-x-syndrome/home/ovc-20164620]; access in ago 9, 2017.

7 – GALANI, A.; KITSIOU-TZELI S.; SOFOKLEOUS C.; KANAVAKIS E.; KALPINI-MAVROU A. Androgen insensitivity syndrome: clinical features and molecular defects. Hormones, 2008, jul-sep; 7(3): 217-29.

8 – EMMANUÈLE, C.; DÉLOT; VILAIN, E. Nonsyndromic 46,XX Testicular Disorders of Sex Development. In: PAGON R.A.; ADAM M.P.; ARDINGER H.H., et al., editors. Gene Reviews. Seattle: University of Washington, 1993.

9 – Prevalence estimates by birth were all taken from the site Genetics Home Reference [https://ghr.nlm.nih.gov/], in ago 9, 2017.

10 - NGUN, ; W. GUO, T. C.; GHAHRAMANI, N. M.; PURKAYASTHA, K.; CONN, D.; SANCHEZ, F. J.; BOCKLANDT, S.; ZHANG, M.; RAMIREZ, C. M.; PELLEGRINI, M.; VILAIN, E. PgmNr 95: A novel predictive model of sexual orientation using epigenetic markers. Available at [https://ep70.eventpilotadmin.com/web/page.php?page=IntHtml&project=ASHG15&id=150123267]; access in ago 9, 2017.

11 – WU, K.J. Between the (Gender) Lines: the Science of Transgender Identity. In: Harvard University. Available at [http://sitn.hms.harvard.edu/flash/2016/gender-lines-science-transgender-identity/]; access in ago 9, 2017.

12 – COELHO, M. Diferenças genéticas, neurobiológicas e físicas entre homens e mulheres e suas explicações naturais. In: Universo Racionalista, ago 6, 2017. Available at [https://universoracionalista.org/diferencas-geneticas-neurobiologicas-e-fisicas-entre-homens-e-mulheres-e-suas-explicacoes-naturais/]; access in ago 9, 2017.

13 – FAYE, J.P. O século das ideologias. Lisboa: Instituto Piaget: 1998.

14 – HORSESHOE Theory. In: Wikipedia: the free encyclopedia. Available at [https://en.wikipedia.org/wiki/Horseshoe_theory]; access in ago 9, 2017.

15 – Ainsworth, C. Sex redefined. In: Nature, 18 fev 2015. Available at [http://www.nature.com/news/sex-redefined-1.16943]; access in ago 8, 2017.

17 – HAMER, D.; HU, S; MAGNUSON, V.; HU, N; PATTATUCCI, A. (1993). "A linkage between DNA markers on the X chromosome and male sexual orientation". Science. 261 (5119): 321–7.

18 – KNAPTON, S. Homosexuality ‘may be triggered by environment after birth'. In: The Telegraph, oct 8, 2015. Available at [http://www.telegraph.co.uk/science/2016/03/15/homosexuality-may-be-triggered-by-environment-after-birth/]; access in ago 10, 2017.

19 – BALTER, M. Homosexuality may be caused by chemical modifications to DNA. In: Science, oct 8, 2015. Available at [http://www.sciencemag.org/news/2015/10/homosexuality-may-be-caused-chemical-modifications-dna/]; access in ago 10, 2017.

20 – KREMER, W. The evolutionary puzzle of homosexuality. In: BBC News, feb 18, 2014. Available at [http://www.bbc.com/news/magazine-26089486]; access in ago 10, 2017.