Sexual reproductionSpec 3.2B
In short
Sexual reproduction involves two parents, each producing gametes that fuse at fertilisation. The offspring inherit a mixture of alleles from both parents, so they are genetically different and there is variation in the population. This means some individuals are likely to survive if the environment changes, but finding a mate takes time and energy.
In sexual reproduction two parents each produce gametes. The gametes fuse at fertilisation, so the offspring inherit a mixture of alleles from both parents. This produces variation in the population.
Sexual reproduction: advantages and disadvantages | Point | Why it matters |
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| Advantage | Variation in the population | If the environment changes or a disease appears, some individuals are likely to have characteristics that let them survive and reproduce. |
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| Disadvantage | Requirement to find a mate | This takes time and energy, and may not always be possible. |
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Common mistake:Sexual reproduction does not make identical offspring, and the offspring are not identical to either parent. Always say they are genetically different.
Written and checked against the Edexcel GCSE Biology (1BI0) specification · Updated October 2026
Frequently asked questions
Why is meiosis important for sexual reproduction?
Meiosis is important because it makes gametes with half the number of chromosomes of a body cell. In humans, sperm and egg cells have 23 chromosomes, so when they fuse at fertilisation the zygote has the full 46. The gametes are also genetically different, which produces variation in the offspring.
What is the difference between mitosis and meiosis?
Mitosis produces genetically identical diploid body cells. Meiosis produces four genetically different haploid gametes, each with half the number of chromosomes of the parent cell. In humans, body cells made by mitosis have 46 chromosomes, while the sperm and egg cells made by meiosis have 23, so fertilisation restores 46.
What are the advantages of sexual reproduction?
Triple only The main advantage of sexual reproduction is variation in the population. Offspring inherit a mixture of alleles from two parents, so if the environment changes or a new disease appears, some individuals are likely to have characteristics that let them survive and reproduce. The disadvantage is that finding a mate takes time and energy.
All 4 questions on Reproduction and meiosis
