Genes are not esoteric knowledge • Gene expression

This item includes a story about a man who discovered that his wife was his half sister.  How would you feel?  The couple already had children.  What would you tell them?  When? 

http://blogs.discovermagazine.com/gnxp/2013/02/genes-are-not-esoteric-knowledge/#.USRb4_1hiK0     /in vitro fertilization IVF sperm donor lesbian advice columnist husband wife half-brother half-sister parent biological father wife three children information for them biological father counselor reproductive technology sort through your emotions healthy children informed of this coefficient of relatedness children’s parents 1/4 genotyped sequenced pedigree constructed products consanguineous relationship would genome signs of inbreeding genetic origins genetic information disseminated manipulated  offspring genetic background adulthood ubiquity personal genomics inbreeding depression higher risk for morbidity later in life incest genetically equivalent avunculate marriage half-siblings aunt uncle niece nephew /