Biological Differences Between Males and Females

The main biological differences between males and females are the fertility and the reproductive organs. Males are continuously fertile from puberty due to the continuous production of sperms whereas females are fertile for 12 hours each month until menopause. Also, male reproductive organs include penis, scrotum, and testicles while female reproductive organs include vagina, uterus, and ovaries.

Males are obviously different from females in terms of their anatomy and physiology due to biological and genetic reasons. Most of these differences are due to the chemical reactions of hormones. 

Key Areas Covered

1. What are Special Biological Characteristics of Males
      – Reproductive System, Hormones, Fertility
2. What are Special Biological Characteristics of Females
      – Reproductive System, Hormones, Fertility
3. What are the Biological Similarities Between Males and Females
     – Outline of Common Features
4. What are the Biological Differences Between Males and Females
     – Comparison of Common Features

Key Terms: Estrogen, Females, Fertility, Males, Progesterone, Testosterone

What are the Special Biological Characteristics of Males

Males have male reproductive structures such as penis, scrotum, and testicles. They produce sperms, the male gametes, which are small and mostly motile. Also, they develop hair on the face at adolescence.

The main sex hormone in males is testosterone, which is responsible for the development of secondary sexual characteristics in males. It is also necessary for the production of sperms in a process known as spermatogenesis, a continuous process from puberty throughout the life. 

Figure 1: Male Anatomy

Males have some amounts of estradiol produced by the conversion of testosterone into it.

What are Special Biological Characteristics of Females

Females only produce eggs, the female gametes, which are comparatively large and non-motile. They have a vagina, a uterus, and ovaries as reproductive structures. They develop a relatively rounded body and enlarged breasts. The two main sex hormones in females are estrogen and progesterone. They are responsible for the development of secondary sexual characteristics in females. 

Figure 2: Female Reproductive Organs

Fertility of females is limited to a certain period of time in their life. Around 500,000 eggs are available by menarche.  With the menopause, they stop the release of eggs.

Biological Similarities Between Males and Females

• The fertility process of both males and females is chemically-driven by means of hormones released from the hypothalamus.
• Both males and females have estrogens.

Biological Differences Between Males and Females 

Reproductive Organs

Males: Have a penis, scrotum, and testicles

Females: Have a vagina, a uterus, and ovaries

Fertility

Males: Continuously fertile from puberty due to the continuous production of sperms

Females: Fertile for 12 hours each month until menopause

Sex Hormones

Males: The main sex hormone is testosterone

Females: The main sex hormones are estrogen and progesterone

Estrogens

Males: Have fewer amounts of estrogen

Females: Have higher amounts of estrogen than males

Genetics

Males: Have one X and one Y chromosome

Females: Have two X chromosomes

Inheritance of Mitochondrial DNA

Males: Mitochondrial DNA of paternal origin does not pass to the next generation

Females: Mitochondrial DNA from maternal origin passes to the next generation

Size of the Brain

Males: Male brain is bigger

Females: Female brain is smaller than male brain

Forehead

Males: Forehead is sloped

Females: Forehead is vertical

Eye Socket

Males: Have squarer eye sockets with blunt upper borders

Females: Have round eye sockets with sharp upper borders

Face

Males: Face is thinner

Females: Face is broader

Vein Size

Males: Have large veins

Females: Have smaller veins

Fat Deposition

Males: Fat deposits around their organs

Females: Fat deposits around the abdomen as a ring

Sounds

Males: Lose the ability to hear high-pitched sounds with age

Females: Lose the ability to hear low-pitched sounds with age

Distinguishing Colors

Males: The ability to distinguish between the shades of colors is less

Females: The ability to distinguish between color shades is high

Blood Flow

Males: The blood flow is evenly concentrated

Females: The blood flow is concentrated around the pelvic region

Metabolism

Males: Obtain more energy from anaerobic respiration

Females: Obtain more energy from aerobic respiration

Conclusion

Males are continuously fertile after puberty while females are fertile only for several hours per month and they become infertile with menopause. Males have male reproductive organs that produce male gametes called sperms while females have female reproductive organs that produce female gametes called eggs. The main biological differences between males and females are the fertility and the reproductive organs.

 Reference:

1. “Sex Differences in Humans.” Wikipedia, Wikimedia Foundation, 18 Apr. 2018, Available here.

Image Courtesy:

1. “Male anatomy Erect” (CC BY-SA 3.0) via Commons Wikimedia
2. “Scheme female reproductive system-en” By CDC, Mysid – Vectorized in Inkscape by User:Mysid from a CDC image (Public Domain) via Commons Wikimedia