This isn't the freaking Middle Ages, if you don't want to become pregnant there's a huge array of means to do so from abstinence to birth control of various flavors all the way up to sterilization. Have all the sex you want because no one cares, just don't be so fucking irresponsible about it that you need to kill to fix your irresponsibility.
You realize that contraception isn't 100% effective right? I know you do, because you've been informed of this fact many times here in P&N.
Additionally, even getting your "tubes tied" can fail.
Even if we're talking 99% success rate (most forms of contraception are lower than this), that's still 1 out of a hundred times that the little swimmers are gonna make it through.
Multiply that by the number of times per day that people have sex nationwide, and we're talking
a lot of failures.