Is the concept of Gandhabba Brahmanical teaching? Is the concept of Gandhabba Brahmanical teaching?

I just wonder the teaching of Gandhabba is not a Buddhist teaching.

‘But do you know
‘Jānanti pana bhonto—

how an embryo is conceived?’
yathā gabbhassa avakkanti hotī’ti?

‘We do know that, sir.
‘Jānāma mayaṃ, bho—
yathā gabbhassa avakkanti hoti.

An embryo is conceived when these three things come together—the mother and father come together, the mother is in the fertile part of her menstrual cycle, and the spirit being reborn is present.’

Idha mātāpitaro ca sannipatitā honti, mātā ca utunī hoti, gandhabbo ca paccupaṭṭhito hoti; evaṃ tiṇṇaṃ sannipātā gabbhassa avakkanti hotī’ti.

https://suttacentral.net/mn93/en/sujato
From MN 93 (though translated by Sujato, I replaced "spirit being reborn" with "gandhabba"), the sentence in question is:


  An embryo is conceived when these three things come together—the
  mother and father come together, the mother is in the fertile part of
  her menstrual cycle, and the gandhabba is present.’
  Idha mātāpitaro ca sannipatitā honti, mātā ca utunī hoti, gandhabbo ca paccupaṭṭhito hoti; evaṃ tiṇṇaṃ sannipātā gabbhassa avakkanti
  hotī’ti.


Pretty much in Buddhism and Hinduism, Gandharvas are a kind of musician devas . According to the wisdomlib page on Gandharvas:


  A Gandharva (Sanskrit) or Gandhabba (Pali) is one of the lowest
  ranking devas in Buddhist theology. They are classed among the
  Caturmaharajikakayika devas, and are subject to the Great King
  Dhrtarastra, Guardian of the East. Beings are reborn among the
  Gandharvas as a consequence of having practiced the most basic form of
  ethics (Janavasabha sutta, DN.18). It was considered embarrassing for
  a monk to be born in no better birth than that of a gandharva.
  
  Gandharvas can fly through the air, and are known for their skill as
  musicians. They are connected with trees and flowers, and are
  described as dwelling in the scents of bark, sap, and blossom. They
  are among the beings of the wilderness that might disturb a monk
  meditating alone.


As stated in the Hinduism.SE answer linked by Dhammadhatu in his comment, Kandarpa is another name for Kamadeva, the cupid god of Hinduism, from the wisdomlib page on Kandarpa:


  Kandarpa (कन्दर्प).—Another name for Kāmadeva. Kāmadeva was born of
  the mind of Brahmā and as soon as he was born he turned to Brahmā and
  asked "Kaṃ darpayāmi?" (Whom should I make proud?) So Brahmā gave him
  the name Kaṃdarpa alias Kandarpa.


It doesn't make sense that a Gandharva is present for conception.

It could make sense that cupid (Kandarpa) is present for conception, so this is the first hypothesis from me. Of course, cupid here could be a personification of romantic or sexual passion. So, this could just mean that sexual passion is present.

From the wisdomlib page on Gandharvavivaha or Gandharva marriage, we find:


  Gāndharvavivāha (गान्धर्वविवाह):—The Gāndharva marriage (vivāha).—This
  is a marriage arising out of the voluntary union of a maiden or her
  lover which springs from desire and has sexual intercourse for its
  purpose. It can be compared with the modern love marriage.


Based on the definition above, once again, "Gandharva" being present, could just mean sexual passion being present.

From the wisdomlib page on apagabbha, we read:


  apagabbha : (adj.) (apa + gabbha) not destined to another rebirth; (a
  + pagabbha) not haughty.
  (Source): BuddhaSasana: Concise Pali-English Dictionary
  
  Apagabbha, (adj.) (a + pa + gabbha) not entering another womb, i. e.
  not destined to another rebirth Vin.III, 3. (Page 50)
  (Source):
  Sutta: The Pali Text Society's Pali-English Dictionary


From this page (quoted from Max Mueller's book "Vinaya Texts"), we see that this comes from the Vinaya, where the Buddha said:


  He who has freed himself, Siha, from the necessity of returning in
  future into a mother's womb, and of being reborn into new existences
  who has rooted out (his being subject to) rebirth, and has done away
  with it, as a palm tree is rooted out, so that it is destroyed and
  cannot grow up again - such a person do I call apagabbha.


So, if "apagabbha" means one who is not destined for descending into a womb, then presumably "pagabbha" means one who is destined for descending into a womb i.e. being to be born. It's possible that "pagabbha" became changed into "gandhabba".

So, these are my two theories:


"Gandhabba being present" just means sexual passion is present.
"Gandhabba being present" was originally "pagabbha being present", meaning the one who is to be born is present.


The second theory originated from Andrei's comment on gabbha.


  ‘But do you know
  ‘Jānanti pana bhonto—
  
  for sure whether that spirit is an aristocrat, a brahmin, a merchant, or a worker?’
  taggha, so gandhabbo khattiyo vā brāhmaṇo vā vesso vā suddo vā’ti?


This part nullifies the first theory, so we are left with the second i.e. "gandhabba being present" was originally (probably) "pagabbha being present", meaning the one who is to be born is present.

This is probably the same meaning as "sambhavesi" in the Karaniya Metta Sutta which according to the wisdomlib page on sambhavesi means:


  sambhavesī : (m.) one who is seeking birth. || sambhāvesi (aor. of
  sambhāveti), esteemed; honoured; mixed with.
  (Source):
  BuddhaSasana: Concise Pali-English Dictionary


It simply means one who is to be born.

The OP asked whether there is a spirit or soul or being that is born or reborn?

If one answers "yes", that would eternalism. If one answers "no", that would be annihilationism.

According to SN 23.2, there is the definition of "being" as follows:


  As he was sitting there he said to the Blessed One: "'A being,' lord.
  'A being,' it's said. To what extent is one said to be 'a being'?"
  
  "Any desire, passion, delight, or craving for form, Radha: when one is
  caught up there, tied up there, one is said to be 'a being.'
  
  "Any desire, passion, delight, or craving for feeling... perception...
  fabrications...
  
  "Any desire, passion, delight, or craving for consciousness, Radha:
  when one is caught up there, tied up there, one is said to be 'a
  being.'


There is another definition of "being" in SN 5.10:


  Why now do you assume 'a being'?
  Mara, have you grasped a view?
  This is a heap of sheer constructions:
  Here no being is found.
  
  Just as, with an assemblage of parts,
  The word 'chariot' is used,
  So, when the aggregates are present,
  There's the convention 'a being.'
  
  It's only suffering that comes to be,
  Suffering that stands and falls away.
  Nothing but suffering comes to be,
  Nothing but suffering ceases.


So, there is a being in Buddhism, but it's not eternal and it is constructed dependent on conditions.

The concept of "rebirth" in Buddhism is simply the continuation of suffering beyond death. There is no eternal person or being or soul or spirit or consciousness or self that dies and is reborn. In fact, it's not even the same being or person or consciousness throughout a single lifetime. It's always changing.

However, looking at the context of the sutta, the Buddha simply wanted to prove that there is no such thing as caste from birth.