My brother had a 50-year-old mother once in one of his old families (the father was 49, I think). And that couple's youngest child was 2 at the time this child was born, so they had two late in life children. Sadly, the father died in his late 50s and the mother at 60, so the kids were left alone at ages 12 and 10.
That was the oldest mother I've ever seen in game - I've had quite a few peeps have children in their late 40s, some at 49, but never 50 or over since that one time.