Abstract: Embodiments described herein relate generally to devices, systems and methods for transplanting and growing human fetal organs within non-human animal hosts. In some embodiments, a method for transplanting an organ from a human fetus in a non-human animal host includes fluidically coupling the fetal organ to the blood circulation system of an immunocompromised non-human animal host such that the organ receives arterial blood flow from the non-human animal host. The blood pressure of the arterial blood flow entering the fetal organ is controlled to be compatible with the blood pressure of the organ from the human fetus. In some embodiments, the blood pressure of the blood flow to the fetal organ is controlled using a blood flow control device that includes an inflatable cuff in pressure contact with a blood vessel of the non-human animal host.