code: private LocalDate childAdjustment(final LocalDate date) {
          if (date == null) {
              return date;
          }
          return date.plusYears(typicals.gapBetweenChildren())
                  .withMonthOfYear(1).withDayOfMonth(1);
      }
docs: Adjust by the gap between children and to beginning of month.
  
  @param date the input date
  @return the adjusted date