It doesn't matter what i believe - it's not a popularity contest of time periods. I'm not a scientist. People who have knowledge and authority to answer this question claim it's ~23 weeks, prior to which a fetus can't even potentially be conscious due to lack of neurons. If old debate was up I'd fish the links out, but you can google it.

Here is one i found now. Last 3 paragraphs should tell you a lot.
http://www.slate.com/id/2120872/