Buying a gift for a 3-month-old can be challenging, as they are still too young to understand the concept of presents. However, there are still many thoughtful and practical gifts you can consider. You may want to consider gifts that will help the baby develop and grow, such as toys that make sounds or have bright colors to stimulate their senses. You can also consider gifts that will make life easier for the parents, such as a diaper bag or a baby carrier. Ultimately, the most important thing is to choose a gift that is thoughtful and shows you care.