Fertility clinic cells (3)
I believe the answer is:
ova
'fertility clinic cells' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ova that I've seen before include "Eggs; sounds like above" , "Prerequisite for procreation" , "Female egg-cells" , "Female egg cells" , "Fertility clinic stock!" .)