Sauna and Hot Tub: Good or Bad?

I'm 15 and I wanted to know - is Sauna and the Jacuzzi (hot tub) good or bad for my health? I want to know the full benefits and cons of them, if possible. I heard that the sauna opens up skin pores, which helps in removing toxins from the body, ergo "cleansing" oneself, BUT I also heard that the temperatures, that are in a sauna/hot tube, are bad for the man parts. Is it true? Because I really wouldn't want that.