The chances of an offspring to have Down syndrome __________ with the mother’s age

The correct option is "Increases".

Down syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. This condition typically occurs due to an error in cell division called nondisjunction, where chromosomes fail to separate properly during the formation of reproductive cells (eggs or sperm).

Scientific studies and clinical data show a strong correlation between maternal age and the incidence of Down syndrome. As a woman ages, the quality of her eggs gradually declines. Specifically, the biological processes governing meiosis in the ovaries become more prone to errors as maternal age increases, particularly after the age of 35.
Consequently, the likelihood of nondisjunction occurring during egg development rises significantly, which directly increases the probability of conceiving an offspring with Down syndrome.