Heredity and Sex
When analyzing the major accomplishments of the 20th century it is imperative to include the achievements in biology, which have revolutionized our understanding of life’s process and of disease. Already in the second half of the 19th century implications to future progress in the biological world were being made. Darwin had outlined the evolution in animal species, Mendel had discovered some basic rules for inheritance, and Weissman and other embryologists were beginning to decipher how an organism develops. (Britannica, 1) However there was one key element missing, how all these advances were correlated? The important information that unified these three fields (heredity, evolution, and development) came at the beginning of the 20th century. This remarkable discovery can be traced back to one person and to one institution: Thomas Hunt Morgan and Columbia University. (Britannica, 1)
Around the turn of the century, scientist’s interest in sex determination intensified. Hundreds of papers written by dozens of scientist were published during 1890-1910. These papers fell into three main clusters, which capitalized on three different approaches to the question on how individuals come to have one sex or the other. (Masienschein, 458) The first, the externalist approach, ascribed sex determination to external conditions that act on the individual in the course of its development. The second, the internalist approach, focused primarily on factors within the individual, maintaining that sex was determined by the egg and manifests itself in morphological or physiological differences within the cytoplasm or nucleus. The last, the hereditarian approach, regarded various inherited “determinants” as basic to ...
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...lity, and special cases of sex-inheritance. (Morgan) Analysis of this book will help one to have a better understanding of heredity and how sexual characteristics are transferred from one generation to another.
Biblography
Maienschein, Jane. What Determines Sex? A Study of Converging Approaches, 1880-1916. Isis © 1984 The History of Science Society
Published by The University of Chicago Press
Morgan, Thomas Hunt. The Application of the Conception of Pure Lines to Sex-limited Inheritanceand to Sexual Dimorphism. American Naturalist, 1911, 45: 65-78
Morgan, Thomas Hunt. Heredity and Sex. Columbia University Press. New York New York, 1914.
Britannica Nobel Prize, Biography Thomas Hunt Morgan, http://www.britannica.com/nobel/micro/404_45.html
Paul, Diane. Controlling Human Heredity: 1865 to the Present. The Control of Nature, New York, 1995.
In Making Sex by Thomas Laqueur, the author analysis sexual differences throughout the 18th century reviewing physicians, scientist, biologist and how society understood the anatomy and physiology of the human body. Laqueur brig us two sex models; the one-sex model and the two-sex model. He explains who we transition from the one-sex model to the two-sex model. How this two models had impacted our society and created an impact in history had it to do with the fact that a lot of evidence was drawn from science. Laqueur also explains how society constructed sex. He takes this investigation in very detail as he explains and investigates sexual differences.
To begin with, gender must be examined at the basic level of science in regard to physical and biological development of humans. We all understand the physical differences between the male and female gender, but how is our sex actually determined. After conception,
Rifkin, Jeremy. "The Ultimate Therapy: Commercial Eugenics on the Eve of the Biotech Century." Writing and Reading Across the Curriculum. 7th ed. Ed.
2)Bryn Mawr College Student Biology Page, good overview of major genetics of sexual orientation studies in last decade
Perkins, H.F.. A Decade of Progress in Eugenics: Scientific Papers of the Third International Congress of Eugenics. 1993 Baltimore: Williams & Wilkins Company.
There are many different facets to the nature versus nurture argument that has been going on for decades. One of these, the influence of nature and nurture on gender roles and behaviors, is argued well by both Deborah Blum and Aaron Devor, both of whom believe that society plays a large role in determining gender. I, however, have a tendency to agree with Blum that biology and society both share responsibility for these behaviors. The real question is not whether gender expression is a result of nature or nurture, but how much of a role each of these plays.
Steen, R. Grant. DNA and Destiny: Nurture and Nature in Human Behavior. New York: Plenum Press, 1996.
Fausto-Sterling, A. (1993, April) The Five Sexes: Why Male and Female Are Not Enough Retrieved from http://moodle.csun.edu
"Eugenics, Genetic Engineering Lite." The Future of Human Evolution. Humans Future, 2010. Web. 14 Feb 2012.
Biological factors (sex) and gender are correlated, but gender may or may not be caused by biological factors. Cherlin proposes four models of how gender is created: the biosocial model, the socialization model, the interactionist model and the patriarchic model. Only the first model, the “biosocial” model, allows for heredity and biological factors to play a role in determining gender. This model is based on the idea that biologically, men and women are predisposed to act a certain way “on average,” but also, that social factors play a strong role in determining whether biological tendencies prevail. According to this theory, biological differences account for only about a quarter of behavioral gender differences while social influences account for the remaining portion. Socialized traits are stronger than biological traits, and can eliminate biological traits, but biological tendencies are still important because it is a challenge for socialized traits to subdue biological traits. A good example of this is outlined in Ke...
[7] Stock, G., and Campbell, J.. "Engineering the Human Germline: an Exploration of the Science and Ethics of Altering the Genes We Pass to Our Children, New York; Oxford University Press, 2000. back
Gender is determined by the sex chromosomes, XX produces a female, and XY produces a male. Males are produced by the action of the SRY gene on the Y chromosome, which contains the code necessary to cause the indifferent gonads to develop as testes (1). In turn the testes secrete two kinds of hormones, the anti-Mullerian hormone and testosterone, which instruct the body to develop in a masculine fashion (1). The presence of androgens during the development of the embryo results in a male while their absence results by default in a female. Hence the dictum "Nature's impulse is to create a female" (1). The genetic sex (whether the individual is XX or XY) determines the gonadal sex (whether there are ovaries or testis), which through hormonal secretions determines the phenotypic sex. Sexual differentiation is not drive...
Savulescu, Julian. “Genetic Interventions and the Ethics of Human Beings.” Readings in the Philosophy of Technology. Ed. David Kaplan. 2nd ed. Lanham: Roman & Littlefield, 2009. 417-430.
One of the major biological differences between males and females are hormones. Hormones that were once thought to only be important for pregnancy and sexual drive are now shown to have profound effects on just about every organ in the body.(*) Some researchers believe that higher exposure to estrogen, in females, or androgens, in males, during fetal development not only causes the sex organs to form but also predisposes the infant to behavior that is typically associated with one gender or the other. (*) For example, girls that were exposed to higher than normal prenatal levels of androgens were more likely than other females to engage in “boy-like” behavior and to play with boy’s toys eve...