Al feliĉulo eĉ koko donas ovojn. | To a fortunate man even a rooster gives eggs. OR To a fortunate person even a chicken gives eggs.
The issue of gender in Esperanto has always been an ambiguous and sometimes awkward one.
A lupo is a wolf, for example, in modern usage usually one of unspecified gender, but originally — and sometimes still — only a male wolf; which meaning is meant nowadays depends entirely on the speaker. One can add -in- to denote a female (lupino), but there’s no comparable way to unambiguously indicate a male wolf — one must resort to an idiomatic and sometimes ambiguous construction with viro* (“adult male human”, “man”) to produce virlupo, which is literally “man-wolf” or “werewolf” but by convention “male wolf”. (“Werewolf” is by convention homlupo, or “human-wolf”; a male werewolf is unintuitively a lupviro — which, adding to the confusion, was the word for “male wolf” in older Esperanto.)
Some writers have attempted to circumvent the problem by coining unambiguously masculine words like taŭro and stalono, a stopgap measure that would obviously be impractical for all animal words.
Kin relationships are still masculine by default; they can be made female with -in-, neutral in the plural with ge-, but not traditionally in the singular — that is, one could say “parents” (gepatroj), but not “parent” without additional word-building or changing words altogether (gepatrano, generinto).
Sometime after 1980, however, the Plena Ilustrita Vortaro included singular gepatro in its pages to mean “either father or mother” while still maintaining that ge- otherwise means “both sexes together”*. This situational use of ge- does not extend beyond kin relationships as an epicene affix; one does not speak of a gelupo in sheep’s clothing, for example, but only a lupo.
One solution to Esperanto’s gender ambiguity problem is the oft proposed -iĉ-, a masculine counterpart to -in- (ex. caridino “tsarevna”, caridiĉo “tsarevich”) which would make words masculine without the ambiguity that vir- brings. However, though -iĉ- has been independently proposed by many people for a long time (mostly as a suffix logically suggsted by -ĉj-, but at least once as a borrowing of the Russian -ич), it has never been made official or been acknowledged in dictionaries.
Resistance to its adoption reportedly has largely* come from the fear that, in some proposals, traditionally male roots like patro (“father”) and viro would become gender-neutral, so that “father” would become patriĉo, “man” viriĉo, and the new usage would not be compatible with the old. (A strangely selective fear, to be sure, since modern usage already conflicts with the old in that ĉevalviro, once “male horse,” is now “centaur”, and al feliĉulo eĉ koko donas ovojn is generally “to a fortunate person even a chicken gives eggs”, and doesn’t make sense anymore.)
The Plena Manlibro de Esperanta Gramatiko characterizes this particular strategy as the proposal of “certain extremists”; the same source is cited in Wikipedia and Wiktionary, but there the strategy is presented as basic to all the proposals for -iĉ-.
Elsewhere, however, -iĉ- is proposed not as a reform to the existing lexicon, but as a clarifying suffix for use only with roots that are already gender-neutral. Patro and viro, both unambiguously male by definition, would remain unchanged — one would no more add -iĉ- to them than one would -in- to amazono (“Amazon”) or damo (“dame”) — but lupo could be masculinized as lupiĉo without any lycanthropic confusion. Moreover, having -iĉ- would make suffixes for either sex optional unless clarification were necessary — a kato, programisto, and amiko would be unambiguously generic words for “cat”, “programmer”, and “friend” instead of the ambiguously masculine/neuter words they’ve been.
Part of the problem with that solution, though, is that in order to avoid neutering traditionally masculine words — something that’s already been happening over the years with words like kuzo, nepo, and others that aren’t intrinsically masculine in some European languages — some twenty new epicene equivalents (mostly denoting kinship relations and titles) would have to be introduced.
To date, this author has never seen more than a handful of such words, so for the interested Esperantist, here’s a more complete list of epicene alternatives to which one can add -in- or -iĉ- as the need arises:*
ESPERANTO MALE DEFAULT
avo | grandfather
edzo | husband
fianĉo | fiancé
filo | son
frato | brother
nepo | grandson
nevo | nephew
onklo | uncle
patro | father
vidvo | widower
kuzo | male cousin
knabo | boy
viro | man
bubo | male brat
fraŭlo | bachelor
grafo | count
princo | prince
reĝo | king
Sinjoro | Mister
koko | rooster
PROPOSED EPICENE COUNTERPART
avolo | grandparent
spozo | spouse
fidancito (fidanci “to betroth”) | fiancé/fiancée
filjo¹ | child
hermano | sibling
nepto¹ | grandchild
nipoto¹ | nephew/niece
zio | uncle/aunt
ĝenitoro | parent
viduvo | widower/widow
kuzeno¹ | cousin
puero | child, young person
homo, adolto, persono | human, adult, person
pueraĉo | brat
celibulo celiba “unmarried” | bachelor/bachelorette
komito² | count/countess
princepo² | prince/princess
rejo² | king/queen
Sioro² | Mister/Mistress/Miss
galinaco³ | chicken
Using these epicene counterparts, a grandparent would be an avolo, a grandfather an avoliĉo, and a grandmother an avolino. The forms avo and avino, while still on the books, would over time become quaint archaisms like bovoviro (originally “bull”, later “minotaur”, and now not used at all).
In 2016, Plena Manlibro de Esperanta Gramatiko dropped its denouncement of -iĉ- as an unnecessary heresy and frankly acknowledged it as a widely proposed — though seldom used — masculine suffix.
In 2019, Plena Manlibro de Esperanta Gramatiko acknowledged that the ambiguities of vir- have likely led to -iĉ- becoming a growing fact in the Esperanto community, though mostly in the forms iĉo and iĉa. It also mentioned a proposed -j- as a gender-neutral answer to -ĉj- and -nj-, as well as a non-binary suffix -ip-.