Why was the discovery of meiosis important for explaining fertilization?

The discovery of meiosis was essential to understanding fertilization because it provided the mechanism that prevents the chromosome number from doubling with every generation.1

Before this discovery, scientists realized that if sperm and egg cells fused, there had to be a way to reduce the number of chromosomes beforehand; otherwise, the resulting zygote would possess an unsustainable, ever-increasing number of chromosomes.1

In 1883, Edouard van Beneden demonstrated that gametes contain only half the number of chromosomes found in body cells. August Weismann subsequently proposed that a specialized form of cell division—meiosis—must exist to account for this reduction. Through meiosis, a diploid cell produces haploid gametes. Consequently, when fertilization occurs, the fusion of two haploid gametes restores the correct diploid number of chromosomes in the offspring, ensuring genetic stability across generations.123