First TV show to feature a kiss between two women:

"L.A. Law"
In the 1991 episode, the character C.J. Lamb kisses her associate, Abby Perkins.
Source: Evening Standard, 10/2/2003

 
   
  TV show that first dealt with masturbation:

"Seinfeld"
The 1992 episode never uses the word, but the plot focuses around the main characters avoiding playing with themselves.
Source: USA Today, 9/24/1999

 
   
  Year a person's bare behind was first shown on network TV:

1983
This occurred on the TV show "Bay City Blues."
Source: USA Today, 9/24/1999

 
   
  Year the first (and only) lead TV character had an abortion:

1972
This occurred on the TV show "Maude."
Source: USA Today, 9/24/1999