<p>The information on Shepard's birthday is considered canon because it was confirmed by the (former) design director for ME 1-3,
here.</p><p>Took me a little while to find it on there, since the formatting appears to have messed up on the text, as it's joined to the end of the 2152 Singapore aftermath entry. </p><p>
</p><p>I'm still puzzled as to what OPs question/confusion was.</p>