1. Trowa has a mysterious past. He may not be human. It is possible that he is alien and may have trouble hiding his antanae unless he uses this hair style.
2. Trowa is human, but suffers from a disease called the "hair-gel overuse syndrome." (puts to much gel on head) This can cause a hair style to be fixed permanently. I do know one thing, the company that manufactures Trowa's hair gel and hair- care poducts has made record profits every year and has share prices rocketing.