Question

When will sex determination in human take place?
A. During fertilization
B. When fertilized ovum takes place
C. During sexual intercourse
D. During fission of the unfertilized egg

Answer 1

Hint: Sex of the new individual depends upon the availability of X or Y chromosome from the male parent in the humans. As female have both sex chromosome as X only so female gamete will always be X chromosome and sex of new individual will depend upon male gamete.

Complete answer:
In human beings, there are 22 pair of autosomal chromosomes and one pair of sex chromosome. Sex chromosomes present in the humans are for male it is XY chromosome and for female it is XX.
So, we can see that a female carries both XX and thus after meiosis it will produce four daughter cells which will have half chromosome that will have only one chromosome with X chromosome. In males, sex chromosome pair is XY thus after meiosis it will generate four daughter cells having two cells with Y chromosome and other two haploid cells with X chromosome.
Thus, we can say that sex of the new individual will be determined by the chromosome that comes from the father. These male and female gametes, that is, ovum and sperm respectively, are produced inside the female and male body. Thus, after intercourse male gamete, that is, sperm enters the environment of female and fertilizes with female gamete that is, ovum. Hence, sex is determined on the bases that which chromosome comes from the father or male gamete.
If from male if X chromosome comes then new zygote will be female that is, XX and if Y chromosome comes from male, the male individual will be formed with XY set of sex chromosome.

Hence, sex will be determined during fertilization so option ‘A’ is correct option.

Note: Please note that sex of new born is not determined by the female this is a myth and society blame only females for it. Biologically male or father is responsible for the sex of new born. Also, bathing male and females is necessary for ecological balance.