If I was a developmental geneticist, I would ask the following two questions:

1) The human heart is initially similar to a  fish heart in the embryo and the hands are initially formed as paddles. Is this a necessary step or is this simply a remainder of the evolutionary history ? 

This question is interesting for me because the stages of development for human embryo  has often been used as an evidence for evolution. If it is found that these traits are simply a remainder of the evolutionary history then the evidence for evolution could become much stronger. This can have great impacts on science and the community by influencing the arguments around evolution vs. revolution. On the other hand, if it is found that these traits are a necessary step in development, then it could have interesting implications for developmental genetics. Why should the hands initially form as paddles and then turn into fingers?  Is there a benefit to having this course of development?

2) When are maternal RNA or proteins deposited into the embryo? Is it before fertilization or after? If it is before fertilization, then at what stage of the egg development are they deposited? If it is after fertilization then what are the mechanisms that signals the mother to deposit them, and how would this work in the case of external fertilization?