loving this thread. like many of the posters, DS is very agile - rolled at two weeks, crawling before fifth month (before he could sit), walking at 9 months. we let him try almost anything, staying within hands reach if we're uncertain. and if we're not worried (he's over 3.5 now) we just watch from afar. freaks some people out - but we know our child. if DD, a few months old, is not so agile, we'll be there for her when she needs it.
i've had quite a few people make concerned comments, or, just lots of looks. one winter i took DS, then desperate to climb stairs and bored to tears in the flat, to climb some steps (rarely used) in a shopping centre during several days of pouring rain. i think it was more the 'dirt' than the 'danger' that frightened people. amazingly, he survived the event with no illnesses. in fact, with all the dirt we've allowed him to access, he's got the constitution of an ox and is rarely ill. have people not heard of how humans acquire immunity?
we also get a lot of five year-olds telling DS that he 'can't' get to the top of a climbing frame. which, usually, he's been climbing for a year and a half or more. he just burns past them, seemingly not understanding their point or why they can't make it.
really heartening to hear there are other parents out there who allow their children to explore and challenge themselves, as much as is possible in this risk-averse society.
oh yes, one more incident. a few months ago was in a staffed playground with a double tyre-swing contraption you're 'meant' to sit on. DS stands up, and was still so small he was able to hold on to the handle bars with ease. i was pushing him around in a circle, slowly, due to PGP (pelvic girdle pain). staff member comes over and says to me that my son needs to sit down. FFS, can't 'I decide what is safe or not safe for my own son?