I think you are missing the point... Conservatives tend to have big families, and their offspring tend to be Conservative too - For every death there should be many children picking up the torch. When my mother leaves this mortal coil, she will leave behind 9 grandchildren, many of voting age. She already has 6 great grandchildren... All but one of my four siblings is dyed-in-the-wool Conservative (albeit that only one of us is Republican, including wives), as are their children. Notice: Of my father's House, one lone member is still Republican, but there are many Conservatives.
The Republican party has been hemorrhaging membership for decades. It isn't demographics. Conservatives have become independents. A fact that the !UP! the middle campaigns of Romney and McCain't failed to acknowledge.
give me a survey that demonstrates Conservatives, on average, have larger than average families.