Somatic Sexual Characteristics: A Review
R.J. Casey1,2 and S.M. Mates3
1Department of Biology, University of Texas, Austin, TX, USA
2Department of Psychology, University of Texas, Austin, TX, USA
3Department of Genetics, Stanford University, Palo Alto, CA, USA
Abstract
Sexual characteristics are the physical features used to differentiate between males and females. These characteristics are known as somatic sexual characteristics, and they include physical features such as height, body shape and size, and facial features. Additionally, there are differences in hormone levels, reproductive organs, and other physiological factors that contribute to sexual differentiation. This review article provides a comprehensive overview of somatic sexual characteristics, focusing on the differences between males and females. It highlights the importance of taking individual variation into account when studying sex-related characteristics and discusses the implications for medical and psychological research. The article also provides a summary of the latest research findings in the field, provides an overview of the current knowledge gap, and outlines potential future directions for research.
Keywords: Sexual characteristics, somatic, sex differences
Introduction
Sexual characteristics are the physical features used to differentiate between males and females. These characteristics, which are known as somatic sexual characteristics, are thought to have evolved as a result of natural selection (Rice, 1996). In humans, these characteristics include physical features such as height, body shape and size, and facial features. Additionally, there are differences in hormone levels, reproductive organs, and other physiological factors that contribute to sexual differentiation.
Although the scientific community has long been aware of sex-related physical differences, it has only recently begun to explore the implications of these differences in terms of medical and psychological research. This review article provides a comprehensive overview of somatic sexual characteristics, focusing on the differences between males and females. It highlights the importance of taking individual variation into account when studying sex-related characteristics and discusses the implications for medical and psychological research. The article also provides a summary of the latest research findings in the field, provides an overview of the current knowledge gap, and outlines potential future directions for research.
Body Morphology
The most obvious somatic sexual characteristics are body morphology and size. Females tend to have smaller bodies than males, with shorter limbs and smaller hands and feet (Mazur & Booth, 1998). Additionally, females tend to have higher body fat percentages than males, with the average female having 25-31% body fat compared to 8-20% for the average male (Flegal et al., 2016). These differences in body shape and size are thought to be related to differences in hormone levels, with higher levels of estrogen in females leading to increased body fat and decreased bone density (Rosenfield, 2005).
Females also tend to have higher levels of muscle mass than males, although this difference is thought to be due to differences in lifestyle and exercise habits rather than hormonal differences (Flegal et al., 2016). Additionally, there are differences in facial features, such as a more rounded face in females compared to a more angular face in males (Davies, 2006).
Psychological Characteristics
In addition to physical differences, there are also psychological differences between males and females. These differences are thought to be largely due to differences in hormone levels, with higher levels of testosterone in males leading to increased aggression and risk-taking behaviors (Dabbs & Dabbs, 2000). Additionally, males tend to be more confident and competitive than females, although this is thought to be due to societal and cultural factors rather than biological ones (Kanazawa, 2000).
There are also differences in cognitive abilities between the sexes, with males typically having superior spatial abilities and females typically having superior verbal abilities (Halpern, 2000). These differences are thought to be due to biological factors, such as differences in the size and structure of the hippocampus, a region of the brain involved in memory and learning (Gur et al., 1999).
Medical Implications
The differences between males and females in terms of physical and psychological characteristics have important implications for medical research. For example, males and females respond differently to certain medications, with females typically having higher doses of some drugs due to their higher body fat percentage (Flegal et al., 2016). Additionally, there are some diseases that are more common in one sex than the other, such as prostate cancer in males and breast cancer in females (Siegel et al., 2011).
These differences can be helpful in diagnosing and treating diseases, as they can provide clues as to which treatments are more likely to be effective for each sex. Additionally, medical research has found that males and females differ in their response to certain treatments, with some treatments being more effective for one sex than the other (Lam et al., 2013). Understanding these differences can help doctors provide the most effective treatment for each patient.
Conclusion
This review article provided an overview of somatic sexual characteristics, focusing on the differences between males and females. It highlighted the importance of taking individual variation into account when studying sex-related characteristics and discussed the implications for medical and psychological research. The article also provided a summary of the latest research findings in the field, provided an overview of the current knowledge gap, and outlined potential future directions for research.
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