I believe it's Surah 86 verse 5-7: "So let man observe from what he was created, He was created from a fluid, ejected, Emerging from between the backbone and the ribs".
The correct translation of sulb is not backbone, nor does the word taraib indicate the mans ribs. Let us review the verse in question:
So let man consider from what he is created. He is created from an emitted fluid that issued from between the sulb and the taraib. (86:5-7)
It is understood the verse to mean that both sulb and taraib refer to the male. In other words, the fluid emitted refers to the semen, and it comes out from in between the sulb and the taraib. However, the truth of the matter is that the word taraibaccording to the Arabicis actually referring to a female body part. Much like the English word penis can only be ascribed to a male, the word taraib can only be applied to a female.
This is not apologetic modernism or revisionism; the classical works of Quranic commentary throughout the last 1400 years confirm this view categorically. In other words, the sulb belongs to the male, and the taraib belongs to the female. This is the view of the Muslims since the last fourteen hundred years, and there is consensus (ijma) on this matter, since the time of the Sahabah (the Prophets disciples) until today.
Shaykh `Abd al-Wahhâb al-Turayrî of IslamToday.com writes:
The phrase mâ dâfiq (emitted fluid) is not restricted in meaning to sperm but is used in Arabic for both the sperm and the egg. Ibn Kathîr, in his commentary on this verse, writes: It emanates from the man and the woman, and with Allahs permission, the child comes forth as a product of both.
The words translated as backbone (sulb) and ribs (tarâib) are not understood in Arabic to belong to the same person. Arabs understand the sulb to refer to a part of the male body and the tarâib to a part of the female. Ibn Kathîr states: It refers to the sulb of the man and the tarâib of the woman
He then quotes this interpretation on the authority of the Prophets companion Ibn `Abbâs. This same understanding is given in all the major classical works of Quranic commentary.
Many non-Arabs misinterpret this verse because they think that sulb and taraib refer to different body parts of the male. In reality, taraib is feminine, and refers to the females body part. For fourteen hundred years, all of the scholars have held this belief, and not a single classical scholar has ever differed on this point. The reason is that the Arabic makes it clear that taraib refers to a feminine body part, and not a male one.
Lanes Lexicon says:
Taraib:
most of the authors on strange words affirm decidedly that it (taraib) is peculiar to women. (Lanes Lexicon, p.301)
All of the major commentaries of the Quran confirm that the taraib is peculiar to women. Ibn Katheer writes in his tafseer (commentary) of the Quran:
It (fluid) emanates from the man and the woman, and with Allahs permission, the child comes forth as a product of both. (Tafseer Ibn Katheer)
Tafseer al-Jalalayn says:
Issuing from between the sulb, of the man, and the taraib, of the woman. (Tafseer Al-Jalalayn)
Tanwir al-Miqbas min Tafseer Ibn Abbas says:
That issued from between the sulb of the man and the taraib of a woman.
(Tanwir al-Miqbas min Tafseer Ibn Abbas)
I hope that you know Arabic and confirm it.