The most straight forward tattoo to signify the importance of a person is a portrait. Though they are the simplest idea, they can be the most detailed and difficult tattoos to perform. Only the most skilled hands should be employed to ink a portrait tattoo, so be sure to view the artist's portfolio when considering one. They are traditionally done in black and gray, but color highlights can be added for effect. Portraits should be done on a relatively flat portion of your body and need to big enough to show adequate detail.
Most birth certificates have a hand and foot print of the children they represent. These prints can be traced and tattooed onto a variety of places on your body. In order to keep with the general theme of inked prints, the tattoo should be done in full black, but you can get creative with the coloring by filling the prints in with the colors of your national flag.
A scripted tattoo of your son's name can also be a simple or extravagant tattoo, depending on font style and letter size. There are literally hundreds of fonts styles to choose from when considering a scripted tattoo, so take your time to pick the best one for you. Also, if you wish to make the tattoo even more personal, you can design the script yourself or if your son is old enough, have him write his name on a piece of paper and have that image tattooed -- an idea made popular by Motley Crue drummer Tommy Lee.
Your son's birth date and initials can be added to any of the previous ideas or represented by themselves. Again, a variety of script styles are available or can be designed yourself for such a tattoo. This string of letters and numbers can be small enough to fit most anywhere on your body if you wish to have a discreet tattoo, and they can be inked in traditional black and gray or in color.