印度教濕婆（Śiva）化身之一的半女自在天為一體兩相造像──身體從中間分為一半，像的右邊為濕婆右半身、左邊為帕爾瓦蒂（Pārvatī）左半身。祂在印度宗教與社會文化歷史中被賦予多元解讀，然而其最初象徵是往世書所記載的交合繁衍的創生力量。濕婆透過此相，賜予梵天製造女性家族，創造具生死、有自主行為和沉淪苦海的眾生，並能自行交合繁衍，增加數量。往世書以人類始祖摩奴（Manu）與其妻百形（Śatarūpā）為例，說明他們交合繁衍所涉及的範疇。其例說明半女自在天的交合繁衍力量，不只是指生理方面的交合與後代繁衍，還包括道德、心理、祭祀等在世生活識與行的因果相續。本文以《濕婆往世書》（Śiva Purāṇa）的兩則宇宙起源神話為例，探討半女自在天交合繁衍的緣由與內容。

The Hindu deity Ardhanārīśvara, one of the incarnations of Lord Śiva, has a body split down the middle comprising two separate parts--the right is Śiva and the left is Pārvatī. Although this specific image has been interpreted from several Hindu and sociocultural perspectives, its foremost symbol is the creative power of procreation as recorded in the Purānic cosmogonic myth. Śiva, in this form, granted Brahmā the ability to produce women and all living things that are “tormented by the fear of birth and death” (janmanṛtyubhayāviṣṭa) and are “immersed in the ocean of suffering by their own independent actions” (karmavaśā vimagnā duḥkhavāridhau), as well the origins of procreation, in order to increase the number of living beings. In regards to human beings, Brahmā, through this creative ability, also produced the progenitors of humanity, the male Manu and the female Śatarūpā, and humanity was thereby continuously propagated. From the perspective of Manu’s genealogy, the procreative power of Ardhanārīśvara not only indicates the physiological aspects of intercourse and the multiplication of descendants, but also encompasses the continuation of karmic consequences related to behavior and consciousness connected to morality, psychology, sacrificial rituals, and other various aspects of life. Based on the two cosmogonic myths described in the Śiva Purāṇa, this article discusses the origins and substance of procreative ideas concerning Ardhanārīśvara