If an adult wishes to get circumcised, then good luck to them. There are many types of cosmetic surgery people get involved with. Other people won't touch cosmetic surgery with a barge pole. Some adults engage in dangerous or unhealthy pastimes. It is their choice.
It would be best if involuntary circumcision was banned completely. Circumcisors would quite rightly be charged with first degree assault. With this scenario, infant circumcision would no longer be taught in medical school.
Obviously there will be a backlash from religious fundamentalists with such a law, so in practice, a law banning involuntary circumcision for non-religious purposes would be more realistic.
Some doctors might be quick to say circumcision to be sometimes medically indicated in older babies. This is highly debatable, for example a tight foreskin is a condition that usually corrects itself. Making involuntary circumcision illegal, except where medically indicated, would still result in a great reduction in circumcisions.
The drawback of course, is that medical indications could be fictitious. Or that a medical opinion could be falsified, for example because one parent wanted their child to be circumcised.
Apparently, in the US, the signature of only one parent is required for a circumcision to happen. This seems to be unnecessarily divisive. What if one parent is for and one against? If the parents are estranged, a vindicative parent may consent to get at the other. It would be much better if both signatures are required.
Why isn't parental consent enough, isn't it their child? A child is not a possession of the parent. Many parents abuse their children in some ways, for example, subjecting them to passive smoking, striking them, sending them to bed without supper, mental cruelty etc. When abuse is very extreme socities typically intervenes. Typically parents are allowed to get away with striking children, but if they cause bruising, bleeding, or breaking bones then intervention can happen. If circumcision is not child abuse then what is?
In Australia, doctors performing circumcision recieve a Medicare rebate. Apparently haemorhagging is common enough to justify a second fee. Governments would be wise to remove the rebate for infant circumsion. Why should the taxpayer pay for someone else unnecesarily having their child tortured? Private health companies should also refuse rebates on it. This is already starting to happen in the US.
For legislative change to happen, politicians must decide on legislative change. The average politician knows very little about circumcision, and its not an issue in their minds. They need to be lobbied on this issue. Politicians can generally be contacted by mail or email.
Education about circumcision is a powerful tool in reducing circumcision. The vast majority of people know very little about circumcision. When a couple has a baby boy they may have him circumcised because its the thing you do, its expected, its what everyone else does, pressure from friends, relatives or doctors, so the boy looks like his Daddy, or any one of many other inane reasons.
The availability of information has reduced the incidence of circumcision. Unfortunately, many people do not actively seek information. They do not research the web. They may believe what a doctor says. Most people get little bits of information from different sources such as TV or glossy magazines and don't question them.
One possibility is for older high school students to study the issue, in particular the history of it and its place in other countries. At school we studied human sexuality in detail, but nothing on the foreskin.
It would be wise for parents contemplating having their child tortured to witness a circumcision first hand. When doing so, they should be in the moment as much as possible, paying attention to their breathing and feelings. They should maintain eye contact with the child.
If a person cannot do this simple thing, then they have no business allowing it to happen to their child.
Another possibility is to witness an adult undergoing the procedure.
Another scenario is to watch a video of a circumcision. Not as powerful as being actually present, but better than nothing.