Originally Posted by Viking_UK

You see plenty of fathers showering with their sons in sport centres and camp sites over here wihtout making a big deal of it. It's just the norm. It's not a sexual situation and also lets your kid know what to expect when puberty hits. It can be a traumatic time for some to suddenly start sprouting hair etc, but at least if they know it's normal, they have less to worry about. It also means that you're more approachable if your kid has any questions about his body and why yours is different to his.
On the hygiene front, it also lets you make sure that your son's getting properly clean.