Answer:
The two situations in which it would be important/useful to be able to predict the phenotype and/or genotype of offspring from a cross include Genetic counseling before marriage so as to enlighten the individuals on the importance and to reduce the risk of having sickle cell offsprings.
The other reason is for paternity and maternity tests. The genotypes and phenotypes are important factors in knowing the paternity of individuals due to the knowledge of genotypic and phenotypic constituents of the individual.