Island of Dr. Love (1979)

Sex and inheritance problems rule the life of Pam and her husband. It seems that Pam's wealthy father has made plans to write her out of the will unless she provides him with a grandchild - Pronto! Worried, they seek out Dr. Steiger, a mysterious psychic physician living on a remote island whose bizarre medical practices take them aback. Both husband and wife begin a series of therapeutic carnal adventures that tear the roof off of their libidos.