When I saw that post by Ann Althouse (guest blogging at Instapundit), I immediately thought the link might be going to this highly popular YouTube video of these Siamese twin girls.

Instead, it went to a picture of edible twin egg yolks.

It's hard to tell whether the yolks are completely separate, so whether the "egg" (would that be plural? Is egg defined only by the shell?) would have hatched into Siamese twin chickens, or hatched at all I do not know. Commercial eggs are often unfertilized. So the author's boyhood concern about destroying two lives might be misplaced.

Of course, the standards for labeling bird and reptile fetal abnormalities seem to be a bit different than the standards for humans. For example, there are plenty of references to "two headed turtle" and "two headed snake" but most people would not call a two headed turtle "Siamese turtle twins" (or "conjoined turtle twins") because they think of them as a unit. This article called "conjoined turtle twins" a turtle:

NORRISTOWN, Pa. - A two-headed turtle captured by a turtle collector is a rare example of a conjoined-twin birth, its owner said.

The turtle would have likely died in the wild because it swims awkwardly and would be an easy target for predators, according to Jay Jacoby, manager of Big Al's Aquarium Supercenter in East Norriton.

The store bought the tiny turtle from the collector for an undisclosed price and will keep it on display, he said.

If the Wiki article about the girls on YouTube is any indication, the term "Siamese twins" seems to be going out of style (at least for humans). Instead, they are referred to as "highly symmetric dicephalic parapagus conjoined twins." (There's also a piece on conjoined twins.)

To illustrate the different standard for humans and animals, in another popular YouTube video (from David Letterman's show),

"Jungle" Jack Hanna shows off Mary Kate & Ashley, the two-headed turtle.

As Hanna points out, each head controls the corresponding leg for its side, which makes it very difficult for the turtle to get anywhere. Were that to happen in humans (as it did with the girls), they'd be considered conjoined (Siamese) twins.

The article on Polycephaly notes the difficulty in line drawing as well as the double standard:

It is difficult to draw the line between what is considered "one animal with two heads" or "two animals that share a body." With humans, dicephalic conjoined twins such as Abigail and Brittany Hensel are considered "twins", i.e., two individuals.[12] This makes sense as there is a range of conjoinedness, and non-dicephalic conjoined twins may be barely-conjoined and separable by surgery, as is the case with Chang and Eng Bunker. Although the Hensel twins only have one pair of arms and legs total, each twin controls one side of the body's limbs. On the other hand, Syafitri, born 2006 in Indonesia, were given one name by their parents because they only had one heart.[13] With other animals, polycephaly is usually described as "one animal with two heads."[3][14] One of the heads, especially in three-headed animals, may be poorly developed and malformed, and not "participate" much.

I guess I'm of two minds about all of this. I'm also of two minds about whether it's "exploitation" to discuss the phenomenon with reference to specific humans as opposed to general terms. Hence, I embedded only the two headed turtle(s). OTOH, the girls don't seem to mind being on YouTube or discussing their condition frankly, but they also say they don't want media attention. So I guess they're of two minds too.

Of two minds?

The more I look at that, the less right it looks.

The more I look at things, the more freaked out I get.

Especially if the things are words. Why is it that they almost always are?

(Maybe I should just say that I'm feeling dicephalic.)