Parent 2 ID Use this field to specify the required variable identifying the second parent in each pedigree . To Specify the Parent 1 ID Variable: Specify the Input SAS Data Set . All of the variables in the specified input data set are displayed in the Available Variables field. Examine the list of available variables. Highlight the variable listing the unique identifiers for parent 2 in the input data set. Click to add the highlighted variable to the Parent 2 ID field, as shown below: