If you think that your genes will forever end if you don't have children, I have to refute this common myth. Heaps of your genes will live on if you have siblings with children or even cousins with children. However, after a few generations the vast most of your genes are diluted into irrelevance anyhow. There is just one single strand of DNA that stays constant thru the males in each generation and one single strand that stays constant thru the females. The "gone in the genepool" forever myth is designed to shame people into having children. It only tends to work to convince morons.
Some of the most accomplished and impressive people in the world.....
-Had no children and lived life to the fullest (Nikola Tesla, Mother Theresa, Pat Buchanan, J Edgar Hoover, Leonardo Da Vinci, Elizabeth Dole, Queen Elizabeth, Hugh Grant! http://www.childfreebychoice.com/history.htm
-or-
-Produced children who were very disappointing and not at all reflective of their high quality.
Ronald Reagan produced Ron Reagan who is an effeminate male feminist, Jimmy Carter produced Amy Carter who is ugly and a college fail-out, Whitney Houston and Bobby Brown produced Bobbi Kristina Brown who was a drug addicted headcase who died very young, Carol Burnett produced Carrie Hamilton who was a drug addict and headcase, Magic Johnson produced EJ Johnson who is a cross dressing fruit loop. The list goes on and on.
Magic Johnson's world class athletic genes produced this:

Bruce Willis and Demi Moore world class looks and talent jointly produced this:

So trust me when I tell you that obsessing about passing on one's "good genes" is a fool's game because your genes express themselves differently with each generation and a genius can produce a feeble-minded Cornfed just as a world class athlete can produce an uncoordinated bookworm with two left feet. Crap shoot at best.
Have kids only because you enjoy RAISING THEM, not to pass on your genes. If not, you'll regret that they did not turn out the way you wanted or that they think differently than you, or that they are a big disappointment. 21 years of expense, worry, inconvenience, and toil is not worth "I jus' wanna pass on muh genes." The world will survive quite well without the "but muh genes" crowd I can assure you.
I'll go further and say that anyone in the "but muh genes" crowd is telegraphing that they would be horrible parents who think that kids succeed based on their genetics, not great parenting. So these are the people who should LEAST likely have children because they think that simply having the kids and letting "muh genes" go to work is the hard part.