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Advantages and disadvantages of sexual and asexual reproduction

Inheritance, variation and evolution · Reproduction · note 3 of 8

Spec 4.6.1.3
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Advantages and disadvantages of sexual and asexual reproductionSpec 4.6.1.3

In short

The main advantage of sexual reproduction is that it produces variation in the offspring, which gives a survival advantage by natural selection if the environment changes. Asexual reproduction needs only one parent, is faster, is more time and energy efficient because no mate is needed, and produces many identical offspring when conditions are favourable. Many fungi use both.

Advantages of each type of reproduction
Sexual reproductionAsexual reproduction
Produces variation in the offspringOnly one parent is needed
If the environment changes, variation gives a survival advantage by natural selectionMore time and energy efficient, as there is no need to find a mate
Natural selection can be speeded up by humans in selective breeding to increase food productionFaster than sexual reproduction
Many identical offspring can be produced when conditions are favourable

The spec lists the advantages. The disadvantages of each type are the converse of the advantages of the other. Sexual reproduction needs two parents, takes more time and energy because a mate must be found, and is slower. Asexual reproduction produces no variation, so if the environment changes, or a new disease appears, the whole population may be affected.

Organisms that use both methods

Some organisms reproduce by both methods, depending on the circumstances. You only need to know the examples below.

  • Malarial parasites reproduce asexually in the human host, but sexually in the mosquito.
  • Many fungi reproduce asexually by spores, but also reproduce sexually to give variation.
  • Many plants produce seeds sexually, but also reproduce asexually by runners (strawberry plants) or bulb division (daffodils).
Exam tip:

You may be asked about an organism you have not met. Use the information given and the general advantages above. 'Conditions are favourable' and 'no mate needed' are common asexual marks. 'Variation' and 'survive a change' are the sexual marks.

Written and checked against the AQA GCSE Biology (8461) specification · Updated October 2026

Frequently asked questions

Why is meiosis important for sexual reproduction?

Meiosis is important because it halves the number of chromosomes in gametes, so that fertilisation restores the full number. Human gametes have 23 chromosomes, and when an egg and a sperm join, the new cell has 46. Meiosis also makes all the gametes genetically different, which leads to variation in the offspring.

What is a genotype and phenotype?

A genotype is the alleles present for a characteristic, such as Bb, and a phenotype is how the characteristic is expressed, such as black fur. The alleles in the genotype operate at a molecular level to develop the characteristics seen in the phenotype. A black mouse could be BB or Bb, but a brown mouse must be bb.

What is a Punnett square used for in genetics?

A Punnett square is used to show the possible combinations of alleles from the gametes of two parents. Each box is equally likely, so it predicts the probability and ratio of the offspring's genotypes and phenotypes. For example, crossing two Bb mice gives a 3 : 1 ratio of black to brown, so a 25% chance of a brown mouse.

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