Actually, I have to think about the days on which my sons were born. They were both born in the BP Hospital in Little Aden when Aden was a British Colony, so they have British birth certificates.
If I remember correctly, they were born on the first day of the week, which is Saturday, but by the time my second son was born two years later, for some reason the weekend days had changed - that sounds daft I know! ... I'll google it:
Okay first son born on a Mondaysecond on a Saturday.
Now I remember, between their births, BP had decided to keep the Moslem weekend instead of the British.