>>14177508The hormones that grow the penis during puberty (HGH, testosterone, IGF and others) are still present in the adult body but of course they do not cause the penis to grow perpetually. The adult penis is desensitized to the signals that stimulated growth during puberty.
If you could somehow resensitize the penis to these signals by turning on the genes relevant for the growth response you'd have a gold mine on your hands. It'd be like a second puberty for your penis only.
