Could it be the tooth?

I think government agencies interested in lowering the reproductive rate may be secretly involved in the bath decor industry.  Think about it.  Why is it toothbrush holders are made with space for 4, and only 4, toothbrushes?  That’s enough for you, your spouse/significant other, and two children.  What about larger families?  Does the bath decor business have no concern for us?  Are we not a viable marketing target?  Do they just assume that with more than 2 kids, we don’t care if we have coordinated bath accessories? 

My theory:  it could be part of a plan to induce population control.