An allergy is an abnormal reaction of the immune system that occurs in response to otherwise harmless substances and is regarded as a medical abnormality.
Even though not a large number of people are allergic to sperm, about two per cent of fertile couples are recorded to have sperm allergies. About 20 to 40 percent of couples with sperm allergies conceive with the help of artificial insemination or an assisted reproductive technology (ART) treatment.