Surely this is the simplest solution? (be warned of a nasty catch when creating these 'quirky updates'. the order of execution of the update is -variable assignments first then column assignments-both left to right!)

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--create the sample table

DECLARE @Sample TABLE (TheName VARCHAR(4),Identifier INT, sex VARCHAR(1))

INSERT INTO @Sample (TheName,Identifier,Sex)

   SELECT 'ABC', 24, 'M' UNION ALL

   SELECT 'ABC',  24,'M' UNION ALL

   SELECT 'LMN',  27, 'M' UNION ALL

   SELECT 'LMN',  27, 'M' UNION ALL

   SELECT 'LMN',  27, 'M' UNION ALL

   SELECT 'PQRS',  25, 'F' UNION ALL

   SELECT 'XYZ',  24, 'M' UNION ALL

   SELECT 'XYZ',  25, 'M'

--@Sex variable only used to force the order of execution of the update

DECLARE @hash VARCHAR(80), @sex VARCHAR(1)

UPDATE @sample

   SET

   @sex=Sex = CASE WHEN COALESCE(@hash,'')

                           <>TheName+CONVERT(VARCHAR(5),Identifier)+sex

           THEN 'd' ELSE SEX END,

   @hash= TheName+CONVERT(VARCHAR(5),Identifier)+sex

DELETE FROM @sample WHERE sex='d'

SELECT * FROM @sample[/font]