title: The sex ratio of normal and manipulated human sperm quantitated by the polymerase chain reaction.
abstract: OBJECTIVE
  To establish the primary sex ratio, the relative abundance of X and Y chromosome-bearing sperm, in unselected sperm and in sperm selected by swim-up or Sephadex filtration (SpermPrep column; Fertility Technologies, Inc., Natick, MA). This was done to evaluate the possibility that these semen manipulations change the primary sex ratio.
  
  
  METHODS
  Ninety-eight unmanipulated semen samples were analyzed for sex chromosome content using quantitative polymerase chain reaction (PCR). A smaller number of samples was analyzed before and after either swim-up or Sephadex filtration.
  
  
  RESULTS
  The mean percentage of all sex chromosomes identified as a Y chromosome in unmanipulated semen samples ranged from 41.9% to 56.7%, with a mean average of 50.3%. There was no significant change in sex chromosome composition after either swim-up (n = 17) or column filtration (n = 20).
  
  
  CONCLUSIONS
  The chromosome compositions of semen samples from a large number of men have equal numbers of X and Y. Swim-up and SpermPrep filtration do not appear to alter the primary sex ratio.
authors.affiliation: Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Boston, Massachusetts 02115.
authors.forename: S M
authors.initials: SM
authors.lastname: Lobel
authors.forename: R J
authors.initials: RJ
authors.lastname: Pomponio
authors.forename: G L
authors.initials: GL
authors.lastname: Mutter
mesh_terms: D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods*; D012016:Reference Values; D012099:Reproductive Techniques; D012730:Sex Chromosomes; D012744:Sex Ratio; D013094:Spermatozoa / Q000502:physiology*; D014998:Y Chromosome