It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Noble Prophet (peace and blessings be upon him) forbade the sale involving deception: Sayyiduna Ibn Umar (may Allah be pleased with them both) says that in the days of ignorance, people used to sell in such a way that by giving a she-camel, they would buy the unborn offspring in the womb of a pregnant she-camel (and would say that when its offspring is born, I will take it). The Noble Prophet (peace and blessings be upon him) forbade this.