Are there any conditions the cause people to have extremely large ears?

Yes: There are a few genetic conditions that do, as well as fragile x syndrome, fetal alcohol syndrome, etc. Truthfully, there's probably just people in the family who have large ears. You can discuss this with your doc or pediatrician, as most worrisome causes of large ears will have other dysmorphic features that can be looked for, and give you a better cause for the large ears.