Creating a default, empty row in Table with user_id fails

Hi, I'm stuck with something quite easy. I've done this before to create
an empty row in a table connected to a current_user...and that looks
like this (placed in the user_controller's create method):

# Creating a default, empty row in Presentations Table
  @presentation = current_user.presentation
  @presentation = current_user.create_presentation unless @presentation

# Creating a default, empty row in Entries Table
  @entry = current_user.entry
  @entry = current_user.create_entry unless @entry

Then I added a third table called Specs and wanted to create the same
thing.

@spec = current_user.spec
@spec = current_user.create_spec unless @spec

But it refuses to create an empty row in the table connected to a
user_id...

Can't understand why...
Models involved are: User.rb & Spec.rb