My revised list of human sexed/gendered features:
- (Primary) Gonads and their gametes -- rigid binary. Are there any intersex gametes?
- (Primary) Genitals -- bimodal
- Secondary anatomical features -- bimodal
- (Secondary) Personality -- much less difference than in common stereotypes, but a little bit. Bimodal?
- (Secondary) Psychological gender identity -- bimodal
- (Tertiary) Gender presentation -- bimodal
We can have a mixture of sexings/genderings of these features.
With respect to the first item: gonads and their gametes...
Some hermaphrodites or intersexed persons may have a hybrid gonad:
en.wikipedia.org
I think the ovarian tissue areas present in an ovotestis can differentiate a progenitor germ cell into a oocyte stem cell and the testis like tissue portion of an ovotestis may differentiate PGC into a spermatozoa stem cell. So, if true, it's not like 0 or 1 but rather can produce 0 and 1.
In humans, most people with ovotesticular disorder are classified as female, having an XX karyotype and a female-typical reproductive tract. Most have one normal ovary, and one undifferentiated ovotestis. In ovotesticular disorder, any combination can occur: two ovotestes, one ovotestis with one ovary, one ovotestis with one testis, or very very rarely one ovary and one testis. Most of the time that ovotestis is sterile, and does not produce gametes at all - in fact, most people with ovotesticular disorder are infertile even if they have one normal gonad. Sometimes, in a female-typical system with a sufficient complement of estrogen/progesterone/luteinizing hormone, the ovotestis can produce ova. Spermatogenesis has never been observed in an ovotestis in a human, and there's only one documented case of a male with ovotesticular disorder having produced fertile sperm.
First off, any sentence you include the word "most" deserves an eyeroll.
Secondly, no. The production of gametes is the question. Round spermatids are gametes.
Fertility is yet another dimension.
To add--Emily writes: "Most have one normal ovary, and one undifferentiated ovotestis."
Applying the word "
undifferentiated" to ovotestis is a bit of a trick. Ovotestes typically have portions that have undergone tissue differentiation into ovarian tissue and other portions that have undergone differentiation into testicular tissue.
See
here:
"
Ovotestes are usually compartmentalized, with connective tissue separating the ovarian components from the testicular components. However, on rare occasions, an intermixture of these elements may occur."
Further, Emily writes an odd sentence, seemingly contradictory:
"Spermatogenesis has never been observed in an ovotestis in a human, and there's only one documented case of a male with ovotesticular disorder having produced fertile sperm."
One would have to imagine that such person who produced fertile sperm had one testis and one ovotestis in order for both clauses to be true, but there's a lot more going on in the clauses...enough to separate them and look deeper.
1. "Spermatogenesis has never been observed in an ovotestis in a human..."
Spermatogenesis is a process of going from primordial germ cell to other intermediate cell types to final mature sperm cell. Typically, in the process, most of these stages are occurring in the testis. However, the final stage of mature gamete occurs in the epididymis. So, depending on how strict or how we want to define the process, we could try to argue that
Spermatogenesis has never been observed in a testis in a human. Technically, it's the beginning and most of the process that occurs in the testicular tissue. I don't particularly support the idea of such strict statements but I leave that as an exercise for the reader and their ideas of semantics.
From
Wikipedia:
Spermatogenesis takes place within several structures of the
male reproductive system. The initial stages occur within the testes and progress to the
epididymis where the developing gametes mature and are stored until
ejaculation. The
seminiferous tubules of the testes are the starting point for the process, where
spermatogonial stem cells adjacent to the inner tubule wall divide in a centripetal direction—beginning at the walls and proceeding into the innermost part, or
lumen—to produce immature sperm.
[2] Maturation occurs in the epididymis.
Consider also the context that I was responding to...i.e. lpretrich's post about gametes. Both immature and mature gametes are gametes. So, testes are producing gametes BEFORE these cells go off to other areas of the body where they become
mature gametes.
The stages of spermatogenesis can be written as
spermatogonium (diploid) -> primary spermatocyte (diploid) -> two secondary spermatocytes (haploid) -> four spermatids (haploid) -> four functional spermatozoids (haploid)
Spermatids are made in the testes and are immature gametes. Their shape is round. Later, in other areas the mature sperm becomes elongated and gains motility as well as losing some superfluous cyto structures. However, a spermatid still is a gamete and through medical assistance apparently can be used for fertilization through injection. Take a look at the following paper:
Many azoospermic men do not possess mature spermatozoa at the time of surgical sperm extraction. This study is a systematic review and meta-analysis evaluating outcomes following round spermatid injection (ROSI), a technique which utilizes immature precursors ...
www.ncbi.nlm.nih.gov
Okay, so the next question ought to be, can an ovotestis produce spermatids? A testis can, so can an ovotestis?
Take a look at the following
paper:
Histologically, the ovotestis had atretic and degraded follicles (Fig.
1A, B), and
spermatogonia, spermatocytes, and round spermatids (Fig.
(Fig.1C).1C). To explore the differentiation potential of ovotestis, we first sought to identify cell types in ovotestis using the single-cell RNA sequencing technology. We collected ovotestis samples from three intersex individuals and dissociated them into single cells for scRNA-seq. The sequencing depth was over 47,000 reads for each cell (Table
S1), median detected genes were 3126 per cell, and median UMIs (unique molecular identifiers) were 9259 (Table
S2). After discarding poor-quality cells, nearly 10,000 cells remained for clustering and typing. To identify cell clusters, we employed a nonlinear dimensionality-reduction technique, UMAP. Together with known marker genes and annotations (Table
S3), 13 cell clusters were identified, including
germline stem cells, primordial oocytes, spermatogonia, spermatocytes, round spermatids, and somatic niche cells (Sertoli and Leydig cells) (Fig.
S1A). UMAP maps showed that each cluster was distinguished from other clusters with marker genes, for example,
nanos2 and
nanos3 in germline stem cells,
kif20a and
kmt5a in spermatogonia B,
spo11 and
meiob in spermatocytes,
izumo1 and
spaca6 in
round spermatids,
amh and
wt1b in Sertoli cells, and
cyp17a1 and
star in Leydig cells (Fig.
S1B).
Emphasis added. So some ovotestes, at least among those in the study, were producing immature gametes that were produced by spermatogenesis and with assistance could be used for fertilization.
2. "...there's only one documented case of a male with ovotesticular disorder having produced fertile sperm"
As near as I can tell this is a claim that comes from 1994 and it isn't clear what it means to be documented, probably peer-reviewed studies in modern society. But in any case, since that time, there have been documented an additional 2. So we're at
3 now.
People with ovotesticular disorder of sexual development who are given a male sex assignment rarely reproduce. Spermatogenesis has been reported in only 12% of these cases, and tubular atrophy with hypoplastic testicular tissue is the norm. There are only 3 reported cases of males with OT-DSD fathering children.
One can expect that as we globalize knowledge and improve fertility technology this number will continue to climb, especially if it is the case that a recommended path is spermatid injection for fertilization and that technology becomes improved upon for these types of cases. (Alabama not included in that prediction).