Let me add my two cents. [I've been using dowels for more than 20 years; tried M&T, but quickly came back to doweling.] From triple dressers to tall chests to exterior doors ... never had a problem.
When properly sized and glued, the wood will yield before the dowel/joint fails.
The surface area of the dowel's embedment [the circumference of the dowel x its imbedment] provides the strength to tensile [pull-apart] forces ... so longer is better. For resistance to shear forces [like those which are produced when stepping on the rung of a ladder], the material and diameter of the dowel are major factors. 90% of the dowels I use fall into three categories: 1/4 x 1 1/4; 3/8 x 2; and 1/2 x 3.