What are your thoughts on having one child vs. more than one child?

Even if you don’t have any children right now, what is you view on having an only-child versus multiple children?

Is an only-child at a disadvantage for having no siblings? Is having more than one child too much? Do you notice any difference between grown-ups that were only-children between grown-ups with siblings?

If you do have children, how many do you have? When the time came, what were your thoughts on having a second child?