Where is the line? Is it okay to use human stem cells for experimentation? Is it okay to grow whole organs for replacement? Is it okay to grow muscles, ears, sk

Where is the line? Is it okay to use human stem cells for experimentation? Is it okay to grow whole organs for replacement? Is it okay to grow muscles, ears, skin, eyes, bones...? Why is not okay to grow them all at once? I don't see any difference. All of this literally is "decephalized humans", just with more modification/specialization and a simpler process. We're even growing brain tissue that exhibits actual human-like brain waves for experimentation - how is that okay with you!?