As far as I know, there is no documented children between Elizabeth and Mary. Four years really isn't that long of a time and gaps happened in royal births all the times: while some Queens had many children and could often be pregnant almost every year, it wasn't true for all of them, and you can have find 2-3 year gaps in many royal houses, if not longer gaps. It's doesn't mean Henry VII wasn't sleeping with his Queen, but possibly just had bad luck and there was no conception. As far as I know, the only other male child Elizabeth had were Arthur, Henry, and Edmund. However, records state they had eight children total, so this supposed son is missing -- it's likely Elizabeth miscarried early into the pregnancy as there is little to no info on said child; still births are still usually recorded even if the child is born dead.