The Catechism in Questions & Answers

227. Did the fall into sin have consequences for all human beings?

Yes. Since the fall into sin, all human beings have been subject to the power of sin. Sin leads to separation from God, in other words, spiritual death: “Therefore, just as through one man sin entered the world, and death through sin, and thus death spread to all men, because all sinned” (Romans 5: 12). The inclination to sin (concupiscence) remains present within mankind. Human beings cannot return to a state of sinlessness through their own power.

Spiritual death: see Questions 89. et seq.

Inclination to sin (concupiscence): Through the fall into sin, a predisposition to sin came into being in man. This is called ‘concupiscence’. It is from this that all sinful thoughts and deeds originate. Even though sins can be forgiven, the inclination to sin remains intact.