Which chromosome pair determines male sex in humans?

Which chromosome pair determines male sex in humans?

• A. XX
• B. XY
• C. YY
• D. XO

Answer: (B)

Sex in humans is determined by the sex chromosomes inherited at fertilization. The crucial factor for male development is the presence of a Y chromosome, which carries the SRY gene that activates testes formation and male differentiation. When the pair is XY, you get a typical male. If the pair is XX, there’s no Y to trigger male development, so the outcome is female. A single X (XO) results in Turner syndrome, which is also female. A YY combination is not a normal viable configuration in humans and does not produce a typical male. So the male-determining chromosome pair is XY.

Sex in humans is determined by the sex chromosomes inherited at fertilization. The crucial factor for male development is the presence of a Y chromosome, which carries the SRY gene that activates testes formation and male differentiation. When the pair is XY, you get a typical male. If the pair is XX, there’s no Y to trigger male development, so the outcome is female. A single X (XO) results in Turner syndrome, which is also female. A YY combination is not a normal viable configuration in humans and does not produce a typical male. So the male-determining chromosome pair is XY.