title: Failure of multitube sperm swim-up for sex preselection.
abstract: OBJECTIVE
  To use double-label fluorescence in situ hybridization to evaluate a modified swim-up procedure that is purported to be effective for preconceptual sex selection.
  
  
  METHODS
  Controlled, blinded study.
  
  
  METHODS
  University hospital laboratories.
  
  
  METHODS
  Donor males reporting for routine semen analysis.
  
  
  METHODS
  Percentages of X- and Y-bearing spermatozoa in neat semen and in two swim-up fractions, determined using double-label fluorescence in situ hybridization.
  
  
  RESULTS
  No clinically significant change from a 1:1 ratio was found in the distribution of X- or Y-bearing spermatozoa after double-label fluorescence in situ hybridization following a modified swim-up procedure and irrespective of the time (15, 30, 45, and 60 minutes) allowed for swim-up.
  
  
  CONCLUSIONS
  Using fluorescence in situ hybridization, a modified swim-up procedure was evaluated for its purported ability to skew the relative percentages of X- and Y-bearing spermatozoa. No clinically significant change in the ratio of X- to Y-bearing spermatozoa was detected independent of time. Therefore, clinical application of this procedure should be strongly discouraged.
authors.affiliation: Department of Obstetrics and Gynecology, University of Nebraska Medical Center, Omaha 68198-3265, USA. CDEJONGE@MAIL.UNMC.EDU
authors.forename: C J
authors.initials: CJ
authors.lastname: De Jonge
authors.forename: S P
authors.initials: SP
authors.lastname: Flaherty
authors.forename: A M
authors.initials: AM
authors.lastname: Barnes
authors.forename: N J
authors.initials: NJ
authors.lastname: Swann
authors.forename: C D
authors.initials: CD
authors.lastname: Matthews
mesh_terms: D015982:Bias; D005298:Fertility; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008297:Male; D008938:Mitosis; D012661:Semen; D012743:Sex Preselection / Q000379:methods*; D013081:Sperm Motility; D013094:Spermatozoa / Q000166:cytology* / Q000502:physiology; D014960:X Chromosome; D014998:Y Chromosome