Do they need all three sciences, or will two do? The answer, backed by Oxford, Imperial and UCL admissions requirements — not guesswork.
Most IGCSE students take at least one science, many take two, and a meaningful proportion take all three. But almost no guide answers the question parents actually ask: does my child need all three sciences, or will two do? And more specifically: does the answer change depending on which university programme they are targeting?
This guide answers both questions directly, using real university admissions requirements rather than vague generalisations. It also works alongside our broader IGCSE subject combination strategy guide for parents planning long-term academic pathways. It covers the science subject pool format, what each science actually tests, when triple science is necessary versus optional, and the role of Additional Maths alongside the sciences.
Plus optional: Additional Maths (0606) for STEM-focused students
The first decision in the sciences pool is not which science — it is which format. Cambridge offers three distinct science qualifications:
The decision that matters most: Separate sciences or combined science is a more consequential choice than which specific sciences to take. Separate sciences keep all A Level options open. Combined science restricts access to individual A Level science subjects at most selective schools — and therefore restricts access to competitive Medicine, Engineering, and Natural Sciences programmes at university.
IGCSE Biology covers cell biology, genetics and inheritance, biological molecules, ecology, human physiology, and plant biology. Assessment is through Paper 1 (multiple choice), Paper 2 (structured questions), and an experimental paper or alternative. The subject rewards careful reading, precise use of biological terminology, and the ability to apply principles to unfamiliar contexts — rather than mathematical calculation.
Biology is the most directly required science for Medicine, Dentistry, Pharmacy, Biomedical Science, and Veterinary Science. Students pursuing these pathways through Cambridge IGCSE programmes are typically expected to maintain strong performance in IGCSE Biology from the earliest stages of Year 10. A student who drops Biology at IGCSE cannot take A Level Biology — and cannot apply to Oxford, Imperial or UCL Medicine. Families considering the medical pathway should also read our complete medicine subject pathway guide. See our Biology tutoring page for the full IGCSE and A Level curriculum map.
IGCSE Chemistry covers atomic structure, bonding, stoichiometry, acids and bases, organic chemistry, rates of reaction, and energy changes. It is more quantitative than Biology — calculations appear throughout — and more conceptually abstract than Physics in its early stages. Paper 6 (alternative to practical) tests experimental design and data interpretation.
Chemistry is the single most universally required science for university applications in Medicine, Dentistry, Pharmacy, Chemical Engineering, Materials Science, and Biochemistry. Across highly competitive international school environments in Dubai and Doha, students targeting selective STEM pathways are increasingly strengthening their foundations through advanced IGCSE Chemistry preparation well before A Levels begin. If only one science beyond Biology is possible for a pre-med student, Chemistry is non-negotiable. Explore our Chemistry tutoring page for IGCSE and A Level support.
IGCSE Physics covers forces, energy, waves, electricity, magnetism, atomic and nuclear physics, and space. It is the most mathematically demanding of the three at IGCSE — equations, numerical calculations, and graph interpretation appear throughout. Students who are strong at Maths typically find Physics more intuitive than the other sciences. Building strong mathematical foundations early makes the transition into Physics significantly smoother. Students who prefer descriptive work often find it the most challenging.
Physics is required for Engineering (all disciplines), Physical Sciences at Cambridge, Architecture, and Computer Science at the most selective universities. Students targeting Engineering or Computer Science often find that strong preparation in IGCSE Physics and Extended Maths becomes increasingly important by Year 11. It is also strongly recommended for Medicine in some international contexts and is a virtual prerequisite for A Level Physics. Our Physics tutoring page covers the full IGCSE syllabus and common paper 4 problem areas.
| Programme | Sciences Required at A Level | IGCSE Implication |
|---|---|---|
| Oxford Medicine | Chemistry + two of: Biology, Physics, Maths | All three sciences separately at IGCSE. Combined Science is insufficient. |
| Imperial Medicine | Chemistry + Biology + one of: Physics, Maths | Separate Biology, Chemistry, Physics at IGCSE. |
| Cambridge Natural Sciences | Two sciences + Maths (three A Levels) | Separate sciences at IGCSE. The specific combination depends on the desired NatSci pathway. |
| Imperial Engineering | Maths + Physics (Grade 7/A minimum) | Separate Physics at IGCSE is essential. Chemistry is strongly recommended. |
| UCL Pharmacy | Chemistry + one of: Biology, Physics, Maths | Separate Chemistry and Biology at IGCSE. |
| Cambridge CS (most took Physics at A Level) | Maths + Further Maths or Physics | Physics at IGCSE is effectively essential for A Level Physics preparedness. |
| General Business / Humanities | No science A Level required | One or two sciences at IGCSE broadens options without excessive commitment. |
Put plainly: if your child might consider Medicine, Dentistry, Veterinary Science, Engineering, Natural Sciences, Pharmacy, or Biomedical Research at a selective university, they should take all three sciences as separate subjects. The pathway is too demanding to leave any part of the science foundation incomplete.
If your child is clearly oriented toward Business, Law, Humanities, or Social Sciences, two sciences is a reasonable position — typically Chemistry and Biology for a flexible general foundation, or Physics and Maths for a technology-adjacent direction. Combined Science is acceptable in this context, though separate sciences remain the stronger choice if the school timetable permits.
The student who takes two separate sciences with strong grades is better positioned than the student who takes three separate sciences and spreads their preparation too thin. Depth matters. But for the STEM pathway, all three separate sciences with good preparation is the gold standard.
IGCSE Additional Maths (0606) is a distinct qualification from IGCSE Extended Maths. It covers topics — trigonometry, calculus, vectors, functions — that appear at A Level Maths from the first week. Students who take Additional Maths and perform well in it arrive at A Level Maths with a measurable advantage over those who took only Extended Maths. This is particularly relevant for students planning engineering, quantitative economics, or computer science pathways.
Additional Maths is worth considering for students targeting A Level Maths, A Level Further Maths, A Level Physics, or Computer Science — particularly students applying to universities where strong mathematical performance will differentiate them. For medicine students whose pathway does not require Further Maths, IGCSE Extended Maths is sufficient. See our Maths tutoring page for the IGCSE Extended and Additional Maths syllabus details.
For the medicine or life sciences pathway, the optimal IGCSE combination is: Maths (Extended), Biology, Chemistry, Physics, English Language, and two to three additional subjects from the humanities or languages pool. This keeps every A Level option open and provides the broadest possible university access.
For students pursuing Engineering, Computing, or quantitative pathways through Pearson Edexcel IGCSE or Cambridge programmes in cities like Singapore and London, subject depth becomes increasingly important by Year 11.
For the engineering or physical sciences pathway: Maths (Extended), Additional Maths, Physics, Chemistry, English Language, and two to three supporting subjects. Computer Science is a strong addition here.
For the general STEM pathway without a defined destination: Maths (Extended), Biology, Chemistry, Physics, English Language, and three subjects from the widest possible pool. Nothing closes. Everything stays open until A Level subject choices in Year 12 narrow the pathway deliberately. Students still exploring long-term STEM positioning should also see our guide to future-proof subject pathways and how STEM students build strong university profiles over time.
We offer 1-on-1 online IGCSE and A Level tutoring in Biology, Chemistry, and Physics — Cambridge and Edexcel. Whether your child needs support in one science or across all three, we build the preparation around their specific combination, timeline, and target grades.
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Related reading: IGCSE Subjects for Medicine · IGCSE Subject Combinations Guide · IB Diploma vs A Levels After IGCSE · Which IGCSE Subjects Are AI-Proof? · The IGCSE Business and Commerce Combination · How Many IGCSE Subjects to Take · IGCSE Past Papers · How to Get A* in IGCSE Maths · Cambridge IGCSE vs Edexcel
