I want to send a workflow email alert to the address in an email field on a record that is the parent of the record being processed.

There doesn't appear to be a way to do that.  I can reference parent fields all I want in the Formula that qualifies the Workflow.  But in the Email alert, when I select "Email Field", I only get Email fields in the actual record, not parent fields available.

The only work around I have found for this restriction is to write Apex code to copy the email field value of the parent into an email field on the child record.  That is really a pain.  It's never good to copy stuff around.  To keep in sync, both objects need update triggers that cascade update other records.

If a formula field could be of type email, I could define a formula field on the child that references the parent field.  But formula fields can't be type email.  (I added an Idea to allow that. feel free to vote up https://success.salesforce.com/ideaView?id=08730000000kwYAAAY.)

Without that feature I can't think of any way to do using definition features, only Apex.

Anyone have any ideas for another workaround for this issue?