The Shu”t R. Akiva Eiger (1- 9) quotes the Besamim Rosh(89)
“Since women didn’t participate in the Machtzis Hashekel
(which went for Karbonos Tzibbur) therefore women are Patur
(exempt) from Tefillas Musaf. (They are Mechuyav (obligated) in
Shachris & Mincha because in those Tefillos we ask for Rachamim)*1
Other Achronim *2 argue on R.A.E. and say if this were true, then
men under 20 yrs., Kohanim & Levi’im according to those
who hold, are exempt from M.H. ,should also be Patur from Tefillas Musaf.
The publisher of the Besamim Rosh was R. Shaul Berlin son of R. Zvi Hirsh Berlin zt"l.
R. Shaul Berlin was a great Talmid Chacham but a Maskil.
He claimed to have found this Ksav Yad of R. Yitzchock d’Molino who compiled the Teshuvos from the Rosh.
It didn’t take long to discover that the Sefer was a forgery and not from the Rosh as R.S.B. claimed.
There is a dispute if the whole Sefer is a forgery or only part of it and some Teshuvos are from the Rosh.
*1 Mishna Veruro 106 sk 4
*2 Magen Giborim