As a rule at the moment of application, less than seven years should have elapsed between the award of a Ph.D. (or equivalent) for each candidate. Extensions of this period may be allowed only in case of eligible career breaks which must be properly documented: maternity (18 months per child born after the PhD award) & paternity leave (accumulation of actual time off for children born after the PhD award) or leave taken for long-term illness, as well as national service.