user39: I've seen several questions so far that deal with human biology as it relates directly to alcohol. 
It seems like these questions are off topic and generally outside of the expertise of this site.
Examples:

Will certain types of beer get me more drunk more quickly?
Why do I seem to pee out more beer than I drink?

How much of this topic can we feasibly cover, and how much of it should we cover?

user13: Jaydles' answer provides some reasonable guidelines for most questions that would reasonably be considered "biology" questions. However, I recommend treating one specific subcategory a bit differently: questions seeking medical advice. 
I hesitate to even bring this up because we haven't actually seen any of these yet, but if past sites on related topics are any indication, a few of them will crop up eventually... And when they do,
Please resist the urge to answer them. Topics such as the treatment of chemical dependency, withdrawal, poisoning, allergies and so on have very serious potential consequences, and those dealing with them should be strongly encouraged to seek out a medical professional. Remember, answers here will be found and read by many, many people beyond just the asker - putting potentially life-threatening advice out on the 'Net is not something we should encourage. 

user38: I'd suggest you allow them for now.  The key question should NOT be:

Couldn't this more accurately be defined as Biology than Beer?

The key question is:

Is this question specifically relevant and of interest to the beer aficionado community?

And these examples seem to pass that test pretty easily.  In my opinion, they are more likely to captivate the attention of the average beer lover than the average biologist. 
Which is why I'd put these squarely in the category of:

Don't worry about fixing a problem until you actually see clear problems.

And in this case, for now, I think you're ok.  

39: <p>I've seen several questions so far that deal with human biology as it relates directly to alcohol. </p>

<p>It seems like these questions are off topic and generally outside of the expertise of this site.</p>

<p>Examples:</p>

<ul>
<li><p><a href="https://alcohol.stackexchange.com/questions/7/will-certain-types-of-beer-get-me-more-drunk-more-quickly">Will certain types of beer get me more drunk more quickly?</a></p></li>
<li><p><a href="https://alcohol.stackexchange.com/questions/16/why-do-i-seem-to-pee-out-more-beer-than-i-drink">Why do I seem to pee out more beer than I drink?</a></p></li>
</ul>

<p>How much of this topic can we feasibly cover, and how much of it <em>should</em> we cover?</p>
 13: <p><a href="https://alcohol.meta.stackexchange.com/questions/3/how-much-do-we-want-to-get-into-biology/21#21">Jaydles' answer</a> provides some reasonable guidelines for <em>most</em> questions that would reasonably be considered "biology" questions. However, I recommend treating one specific subcategory a bit differently: <strong>questions seeking medical advice</strong>. </p>

<p>I hesitate to even bring this up because we haven't actually <em>seen</em> any of these yet, but if past sites on related topics are any indication, a few of them will crop up eventually... And when they do,</p>

<p><strong>Please resist the urge to answer them.</strong> Topics such as the treatment of chemical dependency, withdrawal, poisoning, allergies and so on have <em>very</em> serious potential consequences, and those dealing with them should be strongly encouraged to seek out a medical professional. Remember, answers here will be found and read by many, many people beyond just the asker - putting potentially life-threatening advice out on the 'Net is not something we should encourage. </p>
 38: <p>I'd suggest you allow them for now.  The key question should NOT be:</p>

<blockquote>
  <p>Couldn't this more accurately be defined as Biology than Beer?</p>
</blockquote>

<p>The key question is:</p>

<blockquote>
  <p>Is this question specifically relevant and of interest to the beer aficionado community?</p>
</blockquote>

<p>And these examples seem to pass that test pretty easily.  In my opinion, they are <em>more</em> likely to captivate the attention of the average beer lover than the average biologist. </p>

<p>Which is why I'd put these squarely in the category of:</p>

<blockquote>
  <p>Don't worry about fixing a problem until you actually see clear problems.</p>
</blockquote>

<p>And in this case, for now, I think you're ok.  </p>
