My parents were both 33 when I was born.
I've read though that the age of the grandparents may also be relevant and both my parents were youngest children with, respectively, two and four siblings that were all around ten years older then them. So my paternal grandparents were 41 and 38 when they had my father (they were also related, probably cousins, but not sure, and shared the same family name that only exists in one small village, where they both grew up) and my maternal grandparents must have been around 40 too (don't know their birth dates, though, as they died early).