Can the same page be accessed via https and http version of URL? If so, you may have a duplicate content issue.
You can check whether google has indexed any https URLs using the following:
Couple of solutions to this are what jimsthoughts has suggested in his post above:
a) you can serve a different robots.txt if the request has arrived from https, and control Google access to https in there
b) you can use a canonical link element on all your pages to tell Google that http is the canonical version
There is a third way to address it, and this is to have a list of URLs that should be served as https, and if URL requested is not in this list, to do a 301 redirect to http version, and vice versa (however, be careful to link internally to a correct version of the URL).