When a couple is unable to conceive a child, it is the couple's problem, and not the fault of one partner or the other. Female issues are the most common reasons cited, but some studies suggest that up to 40% of infertility is caused by one or more reasons originating with the male partner.

For men, the problem can only be from one source- the sperm. However, that can involve a variety of difficulties from low sperm count, to poor motility, or abnormal shape/structure of the sperm. In many instances the cause of the sperm difficulties are idiopathic, with no known reason. Some issues may be a result of a past illness, current drug therapy, personal habits such as drinking and smoking, or varicocele veins. Recommendations for improving things like sperm count, include looser clothing around the genitals, eliminating hot baths or hot tubs, giving up alcohol and smoking, and stress reduction.

For women, the difficulties are more varied, and cover a range of functions and issues within her reproductive system. She may have ovulation problems that are due to problems with the thyroid gland, hormone imbalance, and physical or emotional stress. The cervix can also be a cause for concern, either through narrowing, acidic mucous, or a literal sperm allergy. Her uterus may be harboring cysts, fibroids, and polyps, or she may have endometriosis, a condition where tissue from inside the womb, has attached itself somewhere in the abdomen, possibly blocking or restricting normal function of the fallopian tubes and ovaries.

Even when a couple has taken all the recommended tests, some 10% remain infertile, for no known reasons. For them, hormonal fertility treatment or in vitro fertilization, may be viable options for having a family.