I'm at the beginning of the game (Priority: Palaven) and i have not found yet any neutral answer/option, only paragon (top option) and renegade (bottom). In ME and ME2 there were lots of them in the right middle of the conversation wheel.
They were nixed to stop players going SHEP Y U NO INTIMIDATE– kotekzotMar 12, 2012 at 17:58
There are on occasion options in the middle, but they're usually requests for clarification that you can perform before picking a renegade/paragon choice.
There are some neutral choices you can make (neutral in that they give neutral rep) but generally there won't be a paragon, renegade and neutral option. Neutral options might be one of your only choices so they can still be at the top or bottom of the wheel in those cases.
It's a pretty black and white choice 90% of the time.
You are only at the beginning of the game, so their might be some as time goes by.
I believe also in some dialogues that both the bottom and the top options are neutral, however if one is obviously renegade or paragon, then the opposite option will probably be the other as I haven't seen a single option without the counter-option...
This may not be 100% correct (most likely not to be) as I haven't got ME3 yet, although I am a major fan of the series.
There are neutralish responses that will net you +Reputation instead of +Paragon or +Renegade. They aren't located in the center but rather seem to be "less important moral choices"... or non-moral choices.
Just a silly made up example "Commander, should I have Mac & Cheese for lunch or a Hamburger? ... A hamburger sounds good! ... Ok I'll have a hamburger because Shepard rocks! +2 Reputation"
I found a number of this type of discussion while wandering about the Citadel ending arguments between couples and such.