I found out fairly late on that I have a birth defect that means I can't carry. I was quite shocked at how most folk had assumed my childlessness was a lifestyle choice when I first revealed my condition.
Sometimes what I do not have in my life hurts, then I see some sleep deprived parent with a fractious child or a news article on the evils caused by over population and am reminded that some lives are meant to walk a different path and fulfill a different purpose