Inability to conceive or to reproduce successfully may be manifested in barrenness (male or female), abortion, or still-birth. Infertility may arise from inadequate feeding and a resulting poor condition; from adverse environmental conditions or mismanagement (disregard for seasonal cycles of sexual activity); from genital diseases in either male or female; from hereditary or congenital abnormalities in male or female; or from physical or psychical inability or disturbance (incompatibility of male and female blood, old age, discrepancies in size, etc).