There actually have been successful lawsuits in this country brought by men when they were of legal age to sue on their own behalf (there is a statute of limitations for tort cases, so they have to sue within two or three years, generally, of attaining their legal majority).
The problem is, these cases (if they resulted in judgments rather than settlements and result in the creation of new legal holdings) don't bind any courts except the ones they're issued in. So, for example, a state district court decision would only bind future decisions in the same state district court. An appellate level decision at the state court level would only bind the districts under the appeals court. The supreme court of the state would only bind the state's district and appellate courts.
And it's similar at the federal level. The only decisions that bind every court in the country, whether state or federal, are US Supreme Court decisions.
ETA: my point here -- the more suits brought and won, the better, because then more precedents are set and it also gives courts in different jurisdictions a leg to stand on when making new law for their jurisdictions (they can use decisions from out of their jurisdictions as guidance and support, even if those decisions aren't binding precedent).
As far as the 14th Amendment -- I'm not aware of any credible legal authority that deems the 14th Amendment non-binding. It is part of our Constitution and there have been many, many Supreme Court cases applying the 14th Amendment, and not one has ever found it illegitimate or in conflict with another part of the Constitution or that it was not added to the Constitution in a legitimate way. Honestly that is a crackpot argument, that it's not legit.
As far as it applying to protect boys because of the FGM bill, though -- that's simply not how the 14th Amendment works. There is no good legal argument under the 14th Amendment that boys are denied equal protection because of the FGM bill.
I've written about this issue before in these threads:
http://www.mothering.com/discussions...ual+protectionhttp://www.mothering.com/discussions...ual+protectionhttp://www.mothering.com/discussions...ual+protection
My personal opinion as an attorney is that more suits should be brought by individuals against their circumcisers. When it becomes clear to doctors that they will have liability 18-21 years after they circ a baby, that circumcision fee will start to look a lot less attractive. Money talks, and the prospect of having to pay a lot of money down the road when one might otherwise be contemplating retirement, is going to convince a lot more doctors than appeals to their ethical standards.
I would rather see intactivists put the work into finding the right clients, developing these tort cases, and taking them all the way to the end (i.e. judgments rather than settlements, so that some precedents are set), than barking up the tree of either challenging the FGM bill (which is not going to get protection for boys) or passing an MGM bill (which I believe is a political non-starter).