Is the sale of 'habl al-habalah' permissible?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
The sale of 'habl al-habalah' is forbidden. This term refers to the offspring of the offspring, or the offspring of a pregnant animal. Ibn Umar narrated from the Prophet, peace be upon him, that he forbade this sale, and this narration is agreed upon (Muttafaq 'alayh). Furthermore, Ibn Umar stated that the people of Jahiliyyah used to trade the meat of the she-camel until the 'habl al-habalah,' which is when the she-camel gives birth, and then the newborn is also conceived. The Prophet, peace be upon him, forbade them from this transaction (Narrated by Muslim).
Supporting text
This transaction is invalid (fasid). The first type (selling unborn offspring) is invalid because it involves the sale of a non-existent item, and if selling the fetus is impermissible, selling the offspring of the fetus is even more so. The second type (selling until an unknown term) is invalid because it constitutes a sale for an unknown period (majhul al-ajal).