Question 48
Chromosomes, DNA and Sex LinkageThe first four children of a couple were all girls. The probability that the fifth will also be a girl is
- A.1/5
- B.1/4
- C.1/3
- D.1/2.
Show the answer and explanation
Answer: D (1/2.)
Explanation
Each child's sex depends only on whether an X or a Y sperm fertilises the egg. Earlier births make no difference, so the chance is always 1/2.