Libido impairment
Sexual desire can be impaired or reduced. It also may be weak or not be present at all, such as in occurrences of asexuality. Factors of reduced libido can be both psychological and physical. Absence of libido may or may not correlate with infertility or impotence.
Freud viewed libido as passing through a series of developmental stages within the individual. Failure to adequately adapt to the demands of these different stages could result in libidinal energy becoming 'dammed up' or fixated in these stages, producing certain pathological character traits in adulthood. Thus the psychopathologized individual for Freud was an immature individual, and the goal of psychoanalysis was to bring these fixations to conscious awareness so that the libido energy would be freed up and available for conscious use in some sort of constructive sublimation.
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Psychological and Physical Factors