git-send-email is omitting author and date lines

Hi,

sorry if this is a stupid question, but I'm new to git.

When sending a patch to myself using `git-send-email` I realized that
the lines containing the author and the date (lines 5 and 6 in the patch
file) were not in the sent email.

Is this on purpose? And if so, why?

Thanks,
Hp.