The parent that determines the sex of the calf by providing either an X or a Y chromosome in the fertilizing gamete is the:

The parent that determines the sex of the calf by providing either an X or a Y chromosome in the fertilizing gamete is the:

• A. Dam
• B. Sire
• C. Ewe
• D. Heifer

Answer: (B)

Sex is determined at fertilization by the chromosome carried in the sperm. The egg from the mother always has an X chromosome, while the father's sperm can carry either an X or a Y. If the sperm provides an X, the embryo is XX (female); if it provides a Y, it is XY (male). Therefore, the parent that determines the sex by delivering either an X or a Y in the fertilizing gamete is the sire. The dam contributes the egg (X only in mammals) but does not vary to produce different sex chromosomes.

Sex is determined at fertilization by the chromosome carried in the sperm. The egg from the mother always has an X chromosome, while the father's sperm can carry either an X or a Y. If the sperm provides an X, the embryo is XX (female); if it provides a Y, it is XY (male). Therefore, the parent that determines the sex by delivering either an X or a Y in the fertilizing gamete is the sire. The dam contributes the egg (X only in mammals) but does not vary to produce different sex chromosomes.