re: #5 May Day! May Day!

But what’s the difference? Can you explain it rationally?

It could be that the difference is that you know who the father of the child is.

I’ve been told it pertains to Ashkenazim only.

Well, I know that the Yemenite Jews could take more than one wife before they came to Israel. In practice, taking more than one wife was rare even from the times of the Talmud. (Sorry can’t bring a source for that).