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https://canadiancrc.com/newspaper_articles/Globe_and_Mail_Moms_Little_secret_14DEC02.aspx
>In the early 1970s, a schoolteacher in southern England assigned a class science project in which his students were to find out the blood types of their parents. The students were then to use this information to deduce their own blood types (because a gene from each parent determines your blood type, in most instances only a certain number of combinations are possible). Instead, 30 per cent of the students discovered their dads were not their biologically fathers.
>In the early 1970s, a schoolteacher in southern England assigned a class science project in which his students were to find out the blood types of their parents. The students were then to use this information to deduce their own blood types (because a gene from each parent determines your blood type, in most instances only a certain number of combinations are possible). Instead, 30 per cent of the students discovered their dads were not their biologically fathers.
