Principles of Inheritance and Variation Question 216
216. A mother in a family of five daughters is expecting her sixth baby. The chance of its being a son is
(a) zero
(b) 25%
(c) 50%
(d) 100%
Show Answer
Answer : c
Hints & Solution
(c) Humans have 22 pairs of autosomes and 1 pair of sex chromosomes which are $XX$ in females and $XY$ in males. So, everytime the chances of son or daughter is 50-50% depending upon which sex chromosome is contributed by father in sperm.
