Research shows that stereotypes about only children, such as being lonely or spoiled, are often inaccurate. The number of single-child households in the U.S. is rising, with about 20% of families now having only one child. Despite this, stigmas persist. Therapists note that only children sometimes discuss feelings of loneliness in therapy, particularly around holidays and family events, due to having fewer family members for support. As adults, they may seek close friendships to fulfill the role of sibling-like relationships. Therapists suggest that building a supportive community and inviting friends to celebrations can help address these feelings.
https://www.huffpost.com/entry/what-only-child-brings-up-most-in-therapy_l_66d778f1e4b09a3ee66cb844