Tattoos

[Geremia]

For folks reading over our shoulders: Re. the verse above from Leviticus:  we're not bound by OT laws and regulations.

We're not bound by its ceremonial precepts, but we are bound by its moral precepts.
The prohibition to "make in yourselves any figures or marks" is a moral precept, not a ceremonial precept.

What is your basis for this?  If tattoos are a violation of natural law then they must go against some natural end of our human nature.  What would that be? 

It's essentially against the 5th Commandment, as bodily mutilation is against bodily preservation.
There are health risks to tattoos, even if they have been applied with sterile instruments.