git log commit limiting "show commits with >1 child" possible?

My branches are very long so for years I have been doing a lot of scrolling when using gitk. I have just now discovered how to see a simplified history.

For this example history where commits were added in alphabetical order:

A--B--C--D--H
       \
        E--F--G--I
                \
                 J

I do this:

$ git log --graph --branches --simplify-by-decoration --source --oneline
* 00a27e0       J
| * 160d232     I
|/
| * daa5b69     H
|/
* 734db0c       A

and similar in gitk using the View > Edit View > Simple History = 1 This is a great step forward for me! I am very happy with it.

Is there any way to ask git log to additionally display all commits with more than one child, to show where each branch diverges?

So I hope to see:

* 00a27e0       J
| * 160d232     I
|/
* b981ea0       G
| * daa5b69     H
|/
* 546ae44       C
* 734db0c       A

I have read man git-log but I do not understand it all. If there is a way to achieve this then I am not seeing it.

I notice that there is commit limiting by --merges and --no-merges. If --merges means "show only commits with more than one parent", and --no-merges means "show only commits with only one parent", what I want is "show also commits with more than one child".

Or perhaps "show only commits with more than one parent or child".

Is there a way to do this? It will be nice if it also works in gitk. Presently I have git version 1.7.2.3