 Cats are ready to go to new homes at about 12 weeks of age , when they are ready to leave their mother . They can be surgically sterilized ( spayed or castrated ) as early as 7 weeks to limit unwanted reproduction . This surgery also prevents undesirable sex @-@ related behavior , such as aggression , territory marking ( spraying urine ) in males and yowling ( calling ) in females . Traditionally , this surgery was performed at around six to nine months of age , but it is increasingly being performed prior to puberty , at about three to six months . In the US , about 80 % of household cats are neutered . 
