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Which genetic changes can be passed from parents to children?

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Diagram of a DNA double helix showing its twisted ladder structure, with a close-up of the sugar-phosphate backbone, paired nitrogenous bases (adenine, thymine, cytosine, guanine), and labeled nucleotides and hydrogen bonds. — human genome The human genome is made up of approximately three billion base pairs of deoxyribonucleic acid (DNA). The bases of DNA are adenine (A), thymine (T), guanine (G), and cytosine (C).

Genetic changes that can be passed from parents to children are those that occur in the germ cells—specifically the sperm and eggs—which are known as germinal mutations. In contrast, mutations that occur in somatic (body) cells cannot be inherited by offspring.123

Inherited genetic changes can include:

Small-scale mutations: These include point mutations (substitution of a single nucleotide base) or deletions and insertions of several bases, which can lead to genetic disorders.3
Chromosomal abnormalities: These involve changes to the structure or number of chromosomes. While many numerical abnormalities (such as trisomy) occur due to random errors during meiosis, some structural abnormalities—such as translocations—can be inherited from a parent who carries a balanced form of the defect.345

When a mutated gene is passed on, it may result in a genetic disorder, which can be inherited in a dominant, recessive, autosomal, or X-linked manner. It is important to note that while many genetic disorders are familial, some arise for the first time in the germ cells or during early fetal development, meaning the parents may not carry the mutation themselves.3