Al la komentoj pro ĉi tiu mi venis. Seniluziigita mi ne estis.
(Mi esperas, ke tio sencas!)
Kondolencoj sur la lastatempa perdo de via patro, Spock, kaj antaŭe por la perdo de via avo, Sarek.
Mi nomiĝas Inego Montoja. Vi mortigis mian patron, pretigu morti!
Huf! malĝusta kino.
Li ne diras "Luko" en la filmo, li diras "Ne, mi estas via patro". Mandela efekto
You're not wrong, but it's not the "official" usage. Your question is more or less addressed in the Epicene prefixes section of the "Gender reform in Esperanto" Wikipedia page, though probably not to your satisfaction. The gist of it is, that it's generally accepted, but it's not official. I'd recommend reading the rest of the article for a good understanding of gender in Esperanto, and the criticisms and proposed reforms thereof, if you're into that kind of thing.
I'm only going all technical on you to give a more in-depth answer to your question. You'll probably never be given trouble for using "gepatro" for parent, except perhaps from diehard traditionalists, of which I imagine there are a few.
"Mi estas lia patro" = "I am his father"
"Mi estas lia patrino" = "I am his mother"
"Mi estas lia gepatro" = I am his parent" (No gender specified)
I disagree with that in general usage. Gepatro is often used - I just read it in La gazeto for example - to refer to a singular, gender nonspecific, parent. For example; Mi bezonas noton skribitan per gepatro. (I need a note written by a parent, either one, doesn't matter.) Since hermaphroditic parents are actually rather rare it would make sense to use the singular with ge- if either parent fits the bill. I've also seen the prefix used with geavo and gefrato. I suspect it would also work with onklo and kuzo. Outside of family relations it becomes generally useless since then there are other, gender nonspecific, methods to refer to people or animals.
In one discussion I was in it was decided that this was very much in-line with Zamenhof's ideas for the language. I cannot say for certain that it is, but I see nothing in the fundamento which would be a solid basis for a counter argument.
"Gepatro" doesn't exist, unless someone else changed the language later. "Ge-" is a prefix that relates to people of either gender. It's a collective. "Gepatroj" means "father and mother", or even "fathers and mothers".
The language, being a living language, is constantly changing to fit a changing world, gepatro is, to all appearances, one of those changes.
When a teacher asks a modern student to bring a parent to "back-to-school night" the parent that comes might, anymore be either, or both. Saying "Venigu aŭ patron aŭ patrinon" is longer and more clunky than saying "Venigu gepatron."
In the CEED, (Comprehensive English Esperanto Dictionary by Peter Benson, from 1995) one finds under the heading parent "(bio), patr/(in)o, ge~o;" etc. Even Montegue Butler in his Esperanto-English dictionary from 1967 says, and I quote, "The experimental forms geedzo (spouse), gepatro (parent) are theoretically indefensible, but have occasionally been found useful." If you go to the Lernu page www.lernu.net and ask the vortaro, in the strip on the right, to translate "parent" the answer is: parent = gepatro.
So I believe that this term, while unorthodox, and not included in La Fundamento has become an accepted and useful word in Esperanto. Just as komputilo has been accepted to mean computer instead of the old kumputoro and the other half dozen or so words which people tried to fit here, in fact that latter word is still in my CEED.
Star Wars comments, too many there are. ;P
Stel-militojn komentojn, bezonas plu. :D
so why would I am his dad not be acceptable?