Pokémon GO has "full access" to your Gmail account

It has exploded over the last few days with people catching Pokémon using their mobile device’s GPS capability at home, at school, and even at work. Never too old, eh? Issues have arisen with the concept including four suspected robbers luring people to certain locations with the potential of catching Pokémon in Missouri.
When signing into the game players have the option to sign in using their Google account. This, however, gives
full access to their Gmail and all other branches of their Google account if using an iPhone. This issue apparently does not exist when it comes to Android users.