system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: if an identical twin get children, and their children take a DNA test, will it say that they are half brother/sister?

I mean they don't get children together, but they both get a partner and then get children. (No game of thrones)
gpt
In short, yes. Since identical twins have the same DNA, their offspring will then have DNA that suggests that they share a same parent. This emphasized even more if a set of identical twins have kids with another set of identical twins, in which case a DNA test will identify them as full siblings (with respect to genetic similarity).