1. **Problem Statement:** Does having only two daughters mean the husband does not produce sperm bearing a 'Y' chromosome? Explain using a sex determination chart. 2. **Explanation:** Sex determination in humans is based on the combination of sex chromosomes from the parents. Females have two X chromosomes (XX), and males have one X and one Y chromosome (XY). 3. **Sex Determination Chart:** | Parent | Gametes | Offspring Sex | |--------|---------|--------------| | Father | X or Y | XX = Female, XY = Male | | Mother | X | XX = Female, XY = Male | 4. **Interpretation:** The father produces sperm carrying either an X or a Y chromosome. The mother produces eggs carrying only X chromosomes. 5. **Conclusion:** Having only two daughters does not mean the husband does not produce Y-bearing sperm. It is a matter of chance that both children inherited the X chromosome from the father. The Y chromosome sperm are still produced but may not have fertilized the egg in these cases. Final answer: The husband produces both X and Y chromosome-bearing sperm; having only daughters is due to chance, not absence of Y sperm.