Abstract: 
Given a knot in the 3-sphere, its double slice genus is the minimal genus of unknotted surfaces in the 4-sphere that contain the knot as a cross-section. It is straightforward to see the double slice genus is greater than twice the slice genus. One really basic question is whether the double slice genus can be arbitrarily large compared to twice the slice genus. In this talk, I will introduce a lower bound that can be used to answer this question.