Final answer:
The baby boom occurred after World War II due to the return of military personnel, the desire of young Americans to start families, and the economic security of the post-war era.
Step-by-step explanation:
The baby boom occurred right after World War II due to several factors. Firstly, the return of military personnel after the war led to an increase in marriages and a desire to start families. Secondly, young Americans wanted to take advantage of the economic security of the post-war era to have more children. Lastly, the provisions of the GI Bill and the confidence in long-term economic prosperity encouraged couples to have larger families. These factors combined to create a significant increase in birth rates during the baby boom period.