If I may, I'd like to toss a favorite head-canon to the fires of logic and see how it stands up.

What says the group to the claim that Derpy Hooves and Ditzy Doo are, in fact, two separate ponies, perhaps twins? Allow me to present the following evidence for this conclusion:

In Winter Wrap-Up, Derpy is clearly seen twice, once on cloud-clearing detail, and again less than two minutes before another pegasus tells RD that Ditzy left (the wrong direction) to get the southern birds. Now, first, Ponyville has more than enough pegasi to not need to have one on multiple duties, especially one who's... ahem, less than reliable. Secondly, if the same pegasus left that soon before RD was told about it, why didn't she simply stop her instead of running to Dash?

What do you guys think?

I always thought they were different ponies. But, on that note, both Ditzy and Derpy have different color fur as well. Its subtile, but they are different shads of grey.

It's possible that they are 2 different ponies, but are they ever seen in one place? If both of them never come to the same event that decreases the likelihood of them being different ponies exponentionally with every event.

There is also a possibility one of them was a changeling .

Hmm... all interesting theories, and a valid point by 5431041.

5431129 I'm afraid I'm not familiar with the "social upheaval" you mentioned. Is someone throwing a fit about same-sex relationships?

5431142 Ah, I thought perhaps you meant specifically within the fandom.

This is a subject I prefer not to discuss here, as logic will ultimately give way to emotion. Suffice to say that I, having several LGBT friends as well as a wife and daughter who are both bi, must disagree with the position.