User blog comment:Sparrowsong/Is PJO real?/@comment-1897744-20100307072758

Interrupting to ask -- Thalia, one of your grandparents has grey eyes; it's a recessive trait that can skip generations. (Like how I got landed with hazel eyes but have parents with brown and blue - my grandmother, and many of my mom's siblings, have hazel eyes though.) Your parents were both carriers.