Weknow,thepopulationproblemhasbeentheworld'slargestproblem.Bytheyear2000,theworldpopulationreached6billion,over-populationwillbringusmanyproblems,forexamplecancausetrafficcongestion,employmentdifficulty,andsoon.Atpresent,thedevelopmentofChina'sfamilyKouZhanfour5ofallovertheworld.WeChina'sfamilyplanningpolicy,itiseffectivecontrolthenumberofpopulation,reducedtheburden.