Please read the Medical Standards for Appointment, Enlistment, or Induction in the Military Services for yourself. Page 27 http://www.dtic.mil/whs/directives/corres/pdf/613003p.pdf
This is what it says
n. Left varicocele (456.4), if painful or symptomatic, or associated with testicular atrophy, or varicocele larger than the testis.
o. Left varicocele (456.4) that does not reduce or decompress completely when supine.
p. Any Bilateral or right varicocele (456.4).
So, Left Varicocele is only disqualifying if it is painful, symptomatic, it is associated with testicular atrophy or it is larger than the testical and does not reduce or decompress completely when supine. If none of those apply, when you complete your medical history report I would specifically state that it is not (and list each of the disqualifying situations).