Why shouldn't it be the boy's choice to make for himself when he is an adult?
Unless the parents are Jewish, there is no compelling reason why a baby boy needs to be circumcised. According to every professional medical organization that has an official policy on circumcision there is no medical indication for infant circumcision. No professional medical organization in the world recommends that boys should be circumcised.
I feel the same way about any body piercings or tatoos or plastic surgery. They all have risks involved, but if people want to do these things, they should be allowed to do it.
Do you feel that parents should be allowed to pierce their child's body or tattoo their child's body?
In our society body piercings and tattoos are decisions that adults make for their own body, not decisions that parents make for their child's body. Since there is no valid medical indication for infant circumcision, it is just another form of permanent body modification like genital piercing, tattoos, scarification, female genital cutting, etc. In my opinion the only person who can ethically make the decision to permanently modify someone's body is the person himself or herself once he or she is an adult.
Lots of girls get their ears pierced when they are babies.
Parents make those choices too.
Also, many parents make choices about plastic surgery on their kids. Kids ears stick out, and the parents get the surgery done to fix the ears.
My daughter has a scar on her forehead. We've been adviced to get surgery on it. Many parents would do the surgery. We've opted to let her decide when she's an adult. Either decision is okay.