What are the X and Y chromosomes responsible for in offspring?

The X and Y chromosomes are primarily responsible for determining the genetic sex of an offspring in humans and many other organisms. Specifically, the presence of two X chromosomes results in a female, while one X and one Y chromosome leads to a male. This chromosomal mechanism is a fundamental part of sexual reproduction, as it establishes the sex during fertilization when the sperm carrying either an X or Y chromosome combines with the egg, which always carries an X chromosome. The determination of sex is a crucial aspect of genetic inheritance and significantly influences the development of physical traits and reproductive systems in the offspring.

The other choices focus on traits and characteristics that are influenced by different genetic or environmental factors. While traits such as eye color, growth rate, and health status can have a genetic basis, they are not directly determined by the X and Y chromosomes in the same way that sex is. Eye color is controlled by multiple genes, growth rate can be influenced by nutritional factors and overall health during development, and health status can be affected by a combination of genetics, environmental factors, and lifestyle choices.