Section 4 of Chapter 32 Section 4 (1) is hereby amended by adding the following section:

(t) Notwithstanding any general or special law to the contrary, a member in service who took an unpaid leave or leaves of absence in excess of one month due to the birth or adoption of a child(ren) may establish as creditable service the period or periods of unpaid leave in excess of one month by paying into the annuity savings fund of the applicable retirement system before any retirement allowance becomes effective for the member, in a lump sum or in installments, upon the terms and conditions that the applicable board of retirement prescribes, makeup payments of an amount equal to that which would have been withheld as regular deductions for the service the employee otherwise would have paid into the retirement system. Such creditable service buyback shall be limited to a total of two years.