Why do some people have desires for a large family?

I saw on youtube where a married couple already had two children but both of them equally wants a couple more kids. On her 3rd pregnant I think it was either triplet or quads, closing the deal. They got what they wanted.

Then again, they were wealthy. Even if they're financially able, isn't that too much? This might sound weird but long ago, some guy in my HS wanted a large family. We were all just in 11th grade but his goals were finishing school, going to medicine school and find a good woman that wants multiple kids, have a large family. Present-day him and his wife have 3 kids by now and she's pregnant again. He literally followed through with it. At the time no one took his ''I want a large family one day'' words seriously.

I think having two kids is good enough. Why do some people desire more kids? Why do some people want a large family? Is there a logical explanation to that?

Why do some people have desires for a large family?
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