The term "decrease in fertility" refers to a decline in the ability of a person or animal to conceive and have offspring. There are several synonyms for this term including reduced fertility, lowered fecundity, diminished reproductive capacity, impaired reproductive function, and declining fertilities. These synonyms are commonly used in medical and scientific research when discussing factors that affect fertility rates such as age, genetics, lifestyle choices, environmental factors, and certain medical conditions. Overall, the decline in fertility is a growing concern worldwide, and scientists are constantly looking for ways to improve reproductive health and increase fertility rates through various means such as assisted reproductive technologies, lifestyle modifications, and preventative care.