A sexual orietation. Martesexuals are sexually attracted to the Marte™ family. Even though it's it's completely own sexual orientation, it lacks recognition, tolerance&acceptance both from the LGBTQ community as well as the heterosexual community.
*2 lesbians checking out a Marte girl*
A: Oh gosh look at this slayy gurl she's so hot..
B: Omg fr tho!
Both: Nomarte* tho;}
*short for "Not Martesexuell"
