Fertility is related to a man's hormonal health. Changes in virility, which are often influenced by hormones, may signal reproductive problems. Numerous disorders may cause discomfort or swelling in the testicles, with many of them contributing to infertility. The capacity of a guy to keep an erection is often related to his hormone levels.Reduced hormone levels may follow, which might result in difficulty conceiving. Similarly, failure to ejaculate indicates that it may be time to see a doctor. Since the testes contain a man's sperm, testicle health is essential for male fertility. Small or hard testicles may signal possible problems that should be examined by a doctor.