[1] Shady Grove Fertil Reprod Sci Ctr, Rockville, MD USA
[2] NICHD, NIH, PRAE, Bethesda, MD USA
[3] NIH, Bldg 10, Bethesda, MD 20892 USA
[4] Georgetown Univ, Sch Med, Washington, DC USA
[5] Eunice Kennedy Shriver Natl Inst Child, Bethesda, MD USA
[6] Shady Grove Fertil Ctr, Washington, DC USA