D3.2.12—Haemophilia
Haemophilia is an X-linked recessive disorder, so carrier females can have affected sons and affected males pass alleles through daughters.
- Syllabus
- First assessment 2025
- Objective
- D3.2.12
- Level
- HL
Exam analysis
Chance of appearing4%of analysed past papers
Latest appearanceNovember 2021
Most common paperPaper2
Typical marks1–8
Common command terms
- Identify
- Deduce
- Explain
- Outline
- State
- Predict
Recent exam appearances
November 2021Paper2 ["HL"] · TZ02(a)(ii)[ 1 ]D3.2.12—Haemophilia
November 2019Paper1 ["HL"] · TZ012[ 1 ]D3.2.12—Haemophilia
November 2013Paper2 ["HL"] · TZ02(b)[ 2 ]D3.2.12—Haemophilia
May 2013Paper2 ["HL"] · TZ16(c)[ 8 ]D3.2.12—Haemophilia
Practice this objective
Coverage 2013–2021 · Updated 16 Jul 2026
Concept essentials
- Males express an X-linked recessive allele if it is on their single X chromosome.
- Heterozygous females are usually carriers for haemophilia.
- Affected fathers pass their X chromosome to daughters, not sons.