Hi,

You could do it within Conditional Formatting itself as well using AND and COUNTIF.

=AND(COUNTIF($A$2:$A$5,$A2)>1,COUNTIF($B$2:$B$5,$B2)>1,COUNTIF($C$2:$C$5,$C2)>1,COUNTIF($D$2:$D$5,$D2)>1,COUNTIF($E$2:$E$5,$E2)>1)

I used First Name, Last Name, Gender, DOB and SSN for the criteria (columns A, B, C, D, E).

HTH
Steve