Dear Don Chase & Sarah: My sister and I have spent the last three months planning a party for our parents’ 40th wedding anniversary. My world got rocked on Saturdaywhen I was reading the results of my Ancestry.com report. I found out that I have a half-sister who is 38 years old. My father most likely had an affair and conceived her with another woman. I have no idea if this woman knows we are related. Should I tell my mother and my sister what I have learned? If you were me what would you do?