Are "identical cousins" possible?

Realistically Speaking, NO. Simply put, and without getting into specific this is because of the way DNA is mixed around before, during and after fertilisation. Before Coitus (sex) even happens parents will have eggs/sperm that have a DNA thats a mixture of 'their' parents DNA (the kids grand parents), each of these eggs/sperm cells are unique and which one is eventually released at the time of coitus quite random so the firtilising itself if another mixing. and then finally once the egg and sperm get together theres another mixing of genes all over again. Its like doing the impossible not once, not twice, but three times. Incredibly unlikely.

Cousins Identical Cousins

No, but my Mother's brother, married my Father's sister; I have a "double first cousin , that can pass as my twin, and we both have a birth-mark ( mine on my left arm, and her's on her left leg, that are almost identical ! Pretty strange ! PS; There is only 6 days difference in our ages !( And, my Mother was an Identical twin) !

Identical cousins are possible only in a redneck, inbred family. If for instance you married your sister and got her pregnant with identical twins (two eggs fertilized by same sperm at the moment of conception; then yes, they would be identical twins and cousins.

No not even close. My Grandfathers Sister married my Grandmothers Brother. About as close a combination as you can get without any identical twins involved. My dad was five foot six and heavy set, his cousin was Six foot one and lightly build. Its only one case but my guess is no. To look at the two side by side you wouldn't know they were related.

I'm pretty sure I read somewhere if two sets of identical twins had children, there children would be identical cousins. But I can't remember where I read that.

Dear chauncy:

Don’t overthink it. Let me give you the family history of “The Patty Duke Show”, as per Wikipedia.

On the program, the family patriarch is Martin Lane (played by William Schallert). Martin and his wife Natalie (played by Jean Byron), are the parents of Patricia "Patty" Lane (played by Patty Duke).

Martin has an identical twin brother, Kenneth (also played by Schallert). Both men work for the same newspaper – Martin in New York City, Kenneth as a European correspondent. Kenneth married a Scottish woman, and they are the parents of Catherine "Cathy" Margaret Rowan Lane (also played by Duke).

As a consequence of both girls being the offspring of identical twins, they bear a strong family resemblance – one so close that they are indistinguishable, making them truly “identical cousins”. While they could pass for identical twins, they did not, of course, split off from the same ova.

As if this were not confusing enough, they have also a third “identical cousin”, Betsy Lane (also played by Duke), who appeared in one episode of the series. .

In the pilot episode, Cathy comes from Scotland to live with the Martin Lane family and attend high school with Patty (they are identical in age as well as appearance, but that is simply coincidental).

Cathy, having grown up on the European continent, is demure, sophisticated, and fluent in several languages. Patty is a free-spirited, outgoing typical American teenager, whose only second language is American slang.

Their identical appearance leads to never-ending confusion, which forms the basis of the comedic plots. For the sake of the audience, the two girls wear different hair styles. But they can easily exchange hair styles when circumstances demand of it. They are also adept at mimicking each other’s voices (hardly surprising, since they’re played by the same actress).

I was eight years of age when “The Patty Duke Show” came on the air. Having grown up with the Lanes, I was sorry to hear of the passing of Miss Duke. She was a talented actress and stayed active in the business to her dying day. R.I.P.

Flash Kellam

P.S. Yes, there are plenty of cases where identical twin brothers have married identical twin sisters. Some have even had identical twin children! Whether any have had two sets of identical twin children so as to produce “identical cousins”? That I don’t know.

Well if one set of identical twins married another set of identical twins legally their children would be cousins, but genetically they'd be siblings. That's as close as you could get.

yes, it IS theoretically possible. with in vitro fertilization. a fertilized egg splits into 2 identical genetic copies, then one is deposited into two siblings. resulting children would be cousins, and identical twins. in nature, i don't know...apparently inbreeding has been shown to cause identical cousins in mice.....

> Are "identical cousins" possible

Yes, in highly inbred lineages. We have lab mouse lines that are inbred to that point.

We don't inbreed that much in human lineages. The problem is inbreeding depression: expression of deleterious recessives.