I think gamete involvement is probably the least of the qualifications for being a mother or a father. There is so much more involved than DNA. I genuinely see a collection of molecules as something that has very little to do with "mothering" or "fathering".
This one struck me dumb. I have never thought about it this way. What is a father or mother? It is just a genetic link or is it action? I think especially for DE where there is less involvement with the genetic parent that this is a difficult question. I need a third option of "I don't know."