(Adding to previous answers (hope that helps someone):)
Age is simpler but in case of string and with ignoring case:
@fathers.any? { |father| father[:name].casecmp("john") == 0 } should work for any case in start or anywhere in the string i.e. for "John", "john" or "JoHn" and so on.
@fathers.find { |father| father[:name].casecmp("john") == 0 }
@fathers.select { |father| father[:name].casecmp("john") == 0 }