how can you tell if one of your ancestors is adopted on the site ancestry.com?

Answer 1

?? Ancestry is a collection of many types of records. It all depends on if you are looking at something that is a transcription of an original item (leaving it vulnerable to errors), or an image, such as census that IS the original.. which means there are no transcription problems. It doesn't mean that what was told to the census taker was factual, since the census does have errors also. You need to compare the census to alternate records, to be as sure as you can.
My son's birth certificate shows us as parents,since that is standard procedure. Any record we have would also indicate him to be our legal son. Whether or not that holds true for OTHER items, that are found on ancestry... thats just random. I've seen many startling things on census records.. to find something indicating a possible adoption is not unthinkable. Many adoptions as we think of them, were actually very informal where the child was raised by another family, and no legal action taken. The child might be shown in the census with a different name, maybe even identified as "ward".
I would say it ALL depends on exactly what the real record is, when it was done, and even that won't always be exactly what you expect.

Answer 2

I don't know about that but people covered up many things and the records may or may not show the truth. Without good birth control, can you imagine how many children actually were the seed of another?