POWER OF ATTORNEY

      Know  all  by  these presents, that the undersigned hereby constitutes and
appoints  Jonathan  Gillis, VP, Finance of OvaScience, Inc. (the "Company"), and
William  C.  Hicks,  Megan N. Gates, Peter N. Cunningham, Brian J. Shea, Anne T.
Leland  and  Brenda  L. Meyette, each of Mintz, Levin, Cohn, Ferris, Glovsky and
Popeo,  P.C., signing singly, with full power of substitution, the undersigned's
true and lawful attorney-in-fact to:

            (1)    execute  for  and  on  behalf  of  the undersigned, forms and
                   authentication documents for EDGAR Filing Access;

            (2)    do  and  perform  any  and  all acts for and on behalf of the
                   undersigned  which  may be necessary or desirable to complete
                   and execute any such forms and authentication documents;

            (3)    execute  for  and  on  behalf  of  the  undersigned,  in  the
                   undersigned's  capacity  as  an  officer, director and/or 10%
                   shareholder  of  the  Company, Forms 3, 4 and 5 in accordance
                   with Section 16(a) of the Securities Exchange Act of 1934 and
                   the rules thereunder;

            (4)    do  and  perform  any  and  all acts for and on behalf of the
                   undersigned  which  may be necessary or desirable to complete
                   and execute any such Form 3, 4 or 5 and timely file such form
                   with the United States Securities and Exchange Commission and
                   any stock exchange or similar authority; and

            (5)    take  any  other  action of any type whatsoever in connection
                   with   the   foregoing   which,   in   the  opinion  of  such
                   attorney-in-fact,  may be of benefit to, in the best interest
                   of,  or  legally  required  by,  the  undersigned,  it  being
                   understood    that    the    documents   executed   by   such
                   attorney-in-fact,  on  behalf  of the undersigned pursuant to
                   this  Power  of  Attorney,  shall  be  in such form and shall
                   contain  such  terms  and conditions as such attorney-in-fact
                   may approve in such attorney-in-fact's discretion.

      The undersigned hereby grants to each such attorney-in-fact full power and
authority  to  do  and perform any and every act and thing whatsoever requisite,
necessary,  or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could  do  if personally present, with full power of substitution or revocation,
hereby  ratifying  and  confirming  all  that  such  attorney-in-fact,  or  such
attorney-in-fact's  substitute  or substitutes, shall lawfully do or cause to be
done  by  virtue  of  this  power  of  attorney and the rights and powers herein
granted.  The  undersigned acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned, is not assuming, nor
is  the  Company  assuming,  any of the undersigned's responsibilities to comply
with Section 16 of the Securities Exchange Act of 1934.

      This  Power  of  Attorney  shall remain in full force and effect until the
undersigned  is  no longer required to file Forms 3, 4 and 5 with respect to the
undersigned's  holdings of and transactions in securities issued by the Company,
unless  earlier  revoked by the undersigned in a signed writing delivered to the
foregoing attorneys-in-fact.

      IN  WITNESS  WHEREOF, the undersigned has caused this Power of Attorney to
be executed this 16th day of January, 2018.

                                                             /s/ James Lillie
                                                             ------------------
                                                             James Lillie, Ph.D.