The article in the question talks about the changes that can be brought in the DNA and changes in the genetic material of the eggs of the women. These changes that are to be made in the eggs of the women will not only stay till that generation but will go on to further next generations also.
"Designer babies" in this context stand for the babies that are made with changes in the eggs of the women which will have certain specific trait in those babies.
It helps create suspense because a vulture is not a very likely used animal to portray something very pleasant such as a humming bird. A vulture is more looked upon as a threat or very creepy .
