No. I did have two because I wanted two, but I'm an only child and being an only child is fine. It's also a LOT more common these days than when I was a kid growing up. I still had friends who were only children even then, but most often it was due to circumstance rather than intentional choice (ie, mom had a very difficult birth, parents got divorced early on, the child was a "surprise" later in life pregnancy, kid had a sibling but they died young, dad was secretly gay and only got married and had a kid to hide that fact, etc). Nowadays there are plenty of intentionally "one and done" families, which I think is great and a perfectly acceptable and valid way to build a family.