Just because they're older it doesn't mean that seniors aren't getting any. According to a recent survey by Dr. Stacy Lindau and Professor Edward Laumann of the University of Chicago, old age is 'no barrier' to sex life:
In a survey of 3,005 people aged 57 to 85, a significant number said they were sexually active into their 70s and 80s.
Link - Thanks David R!
He could've just asked the 90-year-old Indian guy who just fathered his 21st child!