As we advance in science, more genetic innovations could come about to cure low testosterone in men. Here is another study where Leydig cells were lab grown from stem cells and produced and generated testosterone. Why are Leydig cells important in men? Located in the testes, they produce testosterone in when in presence of Luteinizing Hormone (LH)
https://news.usc.edu/161332/treatment-for-low-testosterone-leydig-cells-human-collagen-research/