D3.2.11—Sex determination
Sex determination in humans depends on X and Y chromosomes, with sperm determining whether the zygote is XX or XY.
- Syllabus
- First assessment 2025
- Objective
- D3.2.11
- Level
- HL
Exam analysis
Chance of appearing3%of analysed past papers
Latest appearanceMay 2023
Most common paperPaper1
Typical marks1
Common command terms
- Identify
- Explain
Recent exam appearances
May 2023Paper1 ["HL"] · TZ124[ 1 ]D3.2.11—Sex determination
May 2015Paper1 ["HL"] · TZ28[ 1 ]D3.2.11—Sex determination
May 2014Paper1 ["HL"] · TZ123[ 1 ]D3.2.11—Sex determination
Practice this objective
Coverage 2014–2023 · Updated 16 Jul 2026
Concept essentials
- Eggs normally contribute an X chromosome.
- Sperm may contribute either an X or a Y chromosome.
- The sperm chromosome determines whether the zygote is XX or XY.