"In my childhood" is the correct one in almost all cases and it can also be used in those rare cases where "in childhood" would be preferred, like for example "he got stuck in childhood". The other one (in childhood) is so rare and situational that I wouldn't bother learning and using it. Common combinations with childhood include "in my childhood", "during my childhood", "during childhood" and "after childhood".

"In childhood" refers to the general experience of children. For example, "Most people learn to read in childhood" "In my childhood" refers to the specific experience of that person. For example, "In my childhood, I learned to read when I was seven."

" In childhood " used when you speak about anyone's childhood in general . " In my childhood " is used when you are speaking about your childhood, it is more specific than the first one . So it depends on the context, if you are speaking generally, you can use the first one . If you are speaking about yourself, you can use the second :)

Great question. Both can be used. But remember it depends on the specific sentence, this dictates the grammar structure. If you are referring to yourself, where you are talking about your childhood, sure "In my childhood will be the way to go - "In my childhood, we always watched the soccer game at the weekend". When this is not starting a sentence, you will probably use In childhood, "Some people learn more effectively in childhood". Other variations, In his childhood, her childhood, during childhood, as a child. But definitely when talking about yourself, just say (for simplicity sake) "In my childhood or "when I was little" I .... blah blah blah -:) Hope this helped! Reach out to me if you need any more questions answered.

As some others have answered, both are correct. Learning a foreign language in childhood is a good idea. (You could add ‘your’ but it isn’t necessary to. Adding it could make the claim seem a little more personal) Her son spent his childhood on his phone. Mine didn’t. (Here, the ‘his’ is necessary because we are pointing out something specific to a childhood that belongs to her son) I had a lot of friends in (my) childhood. Both are possible. From context, it’s obvious that I’m talking about myself so adding it isn’t necessary. But adding it is very natural.