Final answer:
The recombinant fraction for the pericentric inversion of chromosome 8, given that two out of four children were affected, is 50%.
Step-by-step explanation:
The question is asking about the recombinant fraction for a pericentric inversion of chromosome 8 based on the information provided by a student concerning the outcomes of a couple's children. The recombinant fraction is the proportion of offspring that inherit recombinant chromosomes due to crossover events during meiosis. In this case, two of the four children were born with recombinant chromosomes, which suggests a recombinant fraction of 50% since two out of four is equal to ½ or 0.50.