How is sex determined in human beings?
Solution and Explanation
Human beings exhibit male heterogamy. In humans, males (XY) produce two different types of gametes, X and Y. The human female (XX) produces only one type of gametes containing X chromosomes. The sex of the baby is determined by the type of male gamete that fuses with the female gamete. If the fertilizing sperm contains X chromosome, then the baby produced will be a girl and if the fertilizing sperm contains Y chromosome, then the baby produced will be a boy. Hence, it is a matter of chance that determines the sex of a baby. There is an equal probability of the fertilizing sperm being an X or Y chromosome. Thus, it is the genetic make up of the sperm that determines the sex of the baby.
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Notes on Principles of Inheritance and Variation
Concepts Used:
Sex Determination
In human beings and animals, sex determination is usually conducted by hormonal differences, the combination of different chromosomes during reproduction. In human beings, males and females generally hold different gene variants and sex determination is hereditary. Sex differences involve the growth of a human's inner and outer sex organs and genitalia which plays a crucial role in Sex determination into masculinization and feminization that is by the growth of Sertoli cells in a male child and granulosa cells in a female child. As the zygote cell matures into adulthood definite things take place in sexual differentiation, that is the growth of different sex hormones, genes, reproductive glands, and long DNA molecules. The initial stages of sex differentiation in humans are somewhat similar to those of any other mammalian species' biological processes. In humans, males have a pair of XY chromosomes whereas females have a pair of XX chromosomes, and the Y chromosome of the male parent prompts testicular development like testis formation whereas X chromosomes of the male parent prompt ovarian development and form ovaries. Hence it is obvious that Father is the sex-determining factor.