An alternate spelling of "your mom", commonly used on large online communities that prohibit the use of the phrase "your mom" in bio's, messages, motto's, etc. The phrase originated due to the fact that in many fonts, when the lowercase letters "r" and "n" are placed consecutively, they make what looks like a lowercase "m".
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.