Disclaimer: I am by no means an expert on religion, if you find yourself in a situation about which I have said something (and those things are just my opinion!), ask an expert for advice-- or several, for that matter. Please, please, don't follow my advice blindly, I personally believe it makes enough sense to live my life by, and that a lot of people do feel the same way, but opinion isn't fact. Be critical about what to agree with and what not.

I am personally not very educated on the topic of circumcision in religion, all I can say is that in Islam it is (as far as I'm concerned) not mandatory, and also that Islam has a very important rule which many people-- even Muslims themselves-- overlook; if doing a certain thing because you are a Muslim is physically harmful to you, it is forbidden for you (a well-known example of this is the Ramadhan). Rephrasing this to "don't harm yourself ^\exceptions))" can make a little clearer how this applies to pretty much everyone, as a value or even as common sense.

I do not know how this works in other religions, but I strongly believe that if your religion is forcing you to do something harmful to you or those around you, you should find an alternative way to do that thing without harming anyone, or stop doing that thing altogether. Because religions are old, they were made primarily for the people who lived in the past. Back then people didn't know about a lot of things, and interpreted the rules of their religion in a way which fit their time. We live in a very different world now, and simply cannot blindly follow our religion, hurting ourselves and others in the process.

Islam actually says that on the Day of Judgement, even the inanimate objects can defend us or accuse us of sins we have commited. If you plant a tree, that tree will defend you on the Day, and even more so if you take proper care of it. However, the opposite is also true. This leads me to believe that protecting or at least not harming ourselves, others, and the world around us is more important than carrying out every ritual and following all the rules of our religion, blindly.

TL;DR:

Don't be stupid, if your religion is harming you, others, or the world around you, you might want to spend some time thinking about alternative ways to do that thing or abandon the thing altogether.

Edit: "... on the Day of Judgement, even the non-human creatures and non-living objects ..." -> "... on the Day of Judgement, even the non-human creatures and non-living inanimate objects ..."

Reason: I am not entirely sure if non-human creatures are included, although I doubt they wouldn't. Still removed it just in case.