There is a note in the Wikipedia article about conscription in Russia that only sons were not required to serve. I didn't see anything there specifically about Jews.
Lee David Jaffe
Surnames / Towns: Jaffe / Suchowola, Poland ; Stein (Sztejnsapir) / Bialystok and Rajgrod, Poland ; Joroff (Jaroff, Zarov) / Chernigov, Ukraine ; Schwartz (Schwarzman?, Schwarzstein?) / ? ; Koshkin / Snovsk, Ukraine ; Rappoport / ? ; Braun / Wizajny, Suwalki, Poland, Ludwinowski / Wizajny, Suwalki, Poland