The Cynics, on the other hand, argue that since the sex act is good, it should be done even in public. This of course is wrong for a number of reasons, not least of which being that it openly denies both sin and the curse, and rather than looking for forgiveness through the justice of the cross instead actively embraces sin.
All this is not to say that the blessing offered in the command to populate the earth has been completely revoked--just that man has sullied it with his own sin. To use a parallel example, one might use priceless family china as a chamber pot, but that does not mean that one no longer owns the china.
Again, sex was originally (and still is) a blessing and a gift from God for the purpose of filling the earth. To that end, it is not to be reject but rather still may be enjoyed.