About 9% of men and about 11% of women of reproductive age in the United States have experienced fertility problems.1
In one-third of infertile couples, the problem is with the man.
In one-third of infertile couples, the problem can't be identified or is with both the man and woman.
In one-third of infertile couples, the problem is with the woman.
Studies suggest that after 1 year of having unprotected sex, 12% to 15% of couples are unable to conceive, and after 2 years, 10% of couples still have not had a live-born baby.2,3,4 (In couples younger than age 30 who are generally healthy, 40% to 60% are able to conceive in the first 3 months of trying.5)
Fertility declines with age in both men and women, but the effects of age are much greater in women. In their 30s, women are about half as fertile as they are in their early 20s, and women's chance of conception declines significantly after age 35.6 Male fertility also declines with age, but more gradually.
Citations
Chandra, A., Copen, C.E., & Stephen, E.H. (2013). Infertility and Impaired Fecundity in the United States, 1982-2010: Data From the National Survey of Family Growth. National Health Statistics Reports, 67, 1-19. Retrieved February 7, 2018, from https://www.cdc.gov/nchs/data/nhsr/nhsr067.pdf (PDF 328 KB)
Gnoth, G., Godehardt, D., Godehardt, E., Frank-Herrmann, P., & Freundl, G. (2003). Time to pregnancy: Results of the German prospective study and impact on the management of infertility. Human Reproduction, 18(9), 1959–1966.
Dunson, D. B., Baird, D. D., & Colombo, B. (2004). Increased infertility with age in men and women. Obstetrics & Gynecology, 103(1), 51–56.
Practice Committee of the American Society for Reproductive Medicine in collaboration with the Society for Reproductive Endocrinology and Infertility. (2013). Optimizing natural fertility: A committee opinion. Fertility and Sterility, 100(3), 631–637.