Its possible that Ran actually knows Conan is Shinichi, and is simply hiding it.
"The reasoning behind this is that Ran should know that the Fingerprint evidence is Ironclad, meaning Conan HAS to be Shinichi, and in the Cold Case episode, where Conan should have phrased it as "Shinichi's father" instead of Dad, as anyone reading an email from someone else that was sent to them out loud to someone else would normally do. Another piece of evidence is when Ran talked to Conan about giving him her blood while helping Eisuke out to find his birth records. She brings it up, yet does not question how she knew Conan's blood type, or why Conan never questioned it himself. Additionally, back on the Cold Case file, she stops him while reading the email, and while she does not tell him out loud, the images we see imply she recognizes him as Shinichi, because instead of showing the adult Shinichi, we see child Shinichi. She likely then did this to stop him from revealing this in front of Sonoko and Sera, having him quickly make up an excuse in front of both of them so they don't get clued in. When you piece these three moments together, it is reasonable to conclude she not only knows, but is protecting, Conan/Shinichi's identity consciously, though its highly doubtful she knows why.
She can probably conclude though her father cannot be trusted with the truth."
Found this on Ran's profile in Fan Theories tab. Any thoughts about this?