Capacity generally refers to the mental ability of one or both of the parties to the marriage to agree to become husband and wife. Both parties must be of “sound” mind and capable of agreeing to the marriage. Not all forms of mental illness and insanity serve to render someone incapable of entering into a marriage. A common test of capacity is the ability of individuals to understand the nature of marriage and what their responsibilities are to their partners once they enter into the union. Physical incapacity, and in particular the physical inability to have sexual intercourse, does not in and of itself render one incapable of marrying and does not on its face void a marriage that has already occurred.