This Wall Street Journal article is old, but still worth checking out. It reports on twin studies showing that some young kids seem to have a biological predisposition to perfectionist behaviors like getting unreasonably upset if their shoelaces are different lengths, or to "[idolizing] the bodies of models and celebrities."
However, the article is quick to point out that environment factors outweigh the possible genetic ones.
The article also points out some useful solutions, including:
1) Exposure Therapy: "Make small mistakes and do not fix them," she says. Tie your shoes unevenly. Leave a comma or a period out of a paper. "People are not big fans of this at first," she concedes. "But they do learn that a small mistake doesn't make a whole project worthless." A recovering perfectionist herself, Dr. Przeworski says she is crocheting a blanket that is full of dropped stitches." I recommend a similar technique and love her blanket!
2) Using Timers to Delimit Projects: 'I decide on a reasonable time and when the timer is up, I move on.' As a result, she says, 'I get more done and the quality is actually far better than when I uses was going cross-eyed picking every word apart.'" If this works for you, that's fine. I recommend a somewhat different use of the timer in which you, in effect, us it to practice nonperfectionism.
For those who struggle with perfectionism, my book The 7 Secrets of the Prolific includes what is probably the most in-depth discussion of it and its solutions you'll find anywhere.