gistfile1.rb

class Lawyer < ActiveRecord::Base

  def extracted?
    !source.blank?
  end

  with_options :unless => :extracted? do |lawyer|
    lawyer.validates_presence_of :oab,
      :phones,
      :address,
      :day_of_birth,
      :email
    lawyer.validates_associated :phones,
      :address,
      :nextels,
      :cities
  end

end

l = Lawyer.new
l.source = "whatever"
l.valid?  # returns true
l.address = Address.new
l.valid?  # returns false
l.save validate:false
l.reload
l.valid?  # returns true