Human Genetics Problem Set

Problem 9: Sex determination in humans


Why would you predict that half of the human babies born will be males and half will be females?
A. Because of the segregation of the X and Y chromosomes during male meiosis.
Sex is determined by the sex chromosome in the sperm that fertilizes the female egg. Half of the sperm have an X-chromosome and half have a Y-chromosome.
B. Because of the segregation of the X chromosomes during female meiosis.
C. Because all eggs contain an X chromosome.
D. Because, on average, one-half of all eggs produce females.
E. Because of the formation of the Barr body early during embryonic development.

The Biology Project
University of Arizona
Revised: November 5, 1998
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