Your question is not too recent but I did not see anyone touch upon Velocity scripting.
Here is an example from Marketo where the first example is relative to your question:
In this case you would of course need to be aware of the lead's gender in order for it to work. But otherwise as a fallback it will use the First Name token which would be a safer bet than to simply use one form field token in the email.
This would be possible to fix with an Email Script Token (see screenshot)
As with other "My Token"s you can create this directly to the program and if you have many programs (e.g. Email Blasts) you can configure this logic to the folder that they are placed within.