Final answer:
Infertility is medically defined as the inability to achieve a successful pregnancy after at least one year of regular, unprotected intercourse. It encompasses both primary and secondary infertility and can be influenced by a variety of factors, including lifestyle choices and health conditions. So the correct answer is option (C).
Step-by-step explanation:
Infertility is defined as the inability of a sexually mature adult to reproduce by natural means. Specifically, it is characterized scientifically and medically as the failure to achieve a successful pregnancy after at least one year of regular, unprotected sexual intercourse. This duration is the medical standard for diagnosing infertility in individuals without known reproductive issues. Infertility may be classified as either primary or secondary.
Primary infertility is when an individual has never been able to achieve a successful pregnancy. In contrast, secondary infertility is when an individual has been pregnant at least once but is unable to conceive again after trying for a year. About ten percent of U.S. women aged 15 to 44 experience difficulties getting or staying pregnant, indicating the prevalence of infertility.
Factors such as diseases, toxins, stress, poor nutrition, and lifestyle choices like tobacco and marijuana use can contribute to infertility. Additionally, both males and females are equally likely to contribute to infertility in a couple. In the context of the question, the correct answer is that infertility is defined as being unable to conceive after trying for at least 12 months, which corresponds to option c) 12 months.