Since the Septuagint is a translation, scholars speculate if it accurately reflects the Hebrew scriptures of the 2nd century BC. A close examination of the Septuagint and the Masoretic Text (the early Hebrew text of the Old Testament) show slight variations. Were these errors in translation, or are the Septuagint and Masoretic Text based on slightly different Hebrew manuscripts? The discovery of the Dead Sea Scrolls has helped to shed light on this question. Discovered in the Qumran region near the Dead Sea beginning in 1947, these scrolls are dated to as early as 200 BC and contain parts of every book in the Old Testament except Esther. Comparisons of the Dead Sea Scrolls to the Masoretic Text and the Septuagint show that where there are differences between the Masoretic Text and the Septuagint, approximately 95% of those differences are shared between the Dead Sea Scrolls and the Masoretic text, while only 5% of those differences are shared between the Dead Sea Scrolls and the Septuagint. Does this mean that the Septuagint is unreliable and that our Old Testament is wrought with contradictory sources? No. It is imperative to note that these “variations” are extremely minor (i.e., grammatical errors, spelling differences or missing words) and do not affect the meaning of sentences and paragraphs. (An exception is the book of Jeremiah, in which the actual passages are arranged differently.) None of the differences, however, come close to affecting any area of teaching or doctrine. The majority of the Septuagint, Masoretic Text and the Dead Sea Scrolls are remarkably similar and have dispelled unfounded theories that the Biblical text has been corrupted by time and conspiracy. Furthermore, these variations do not call into question the infallibility of God in preserving His word. Although the original documents are inerrant, translators and scribes are human beings and are thus prone to making slight errors in translation and copying (Hebrew scribal rules attest to how exacting scribes were). Even then, the Bible has redundancy built into its text, and anything significant is told more than once. If grammatical mistakes were introduced that makes a point unclear, it would be clarified in several other places in scripture.
For example, in 1 Samuel 25:22, in the KJV, David's threat is spelled out clearly, in the form he actually used: "So and more also do God unto the enemies of David, if I leave of all that pertain to him by the morning light any that pisseth against the wall."
In the NASB, it reads: "May God do so to the enemies of David, and more also, if by morning I leave as much as one male of any who belong to him."
In the first, it's clear that David is saying that any male who is not a babe in arms (old enough to stand up and urinate against a wall) will be dead by morning, if Nabal did not grant his requests. The second is cleaned up.
Even the KJV used euphemisms instead of the actual Hebrew.
In Genesis 24:9 "And the servant put his hand under the thigh of Abraham his master, and sware to him concerning that matter." the term is a euphemism. Bonds of promise were made by the parties not putting their hands under the other's thighs, but by gripping each other's testicles.
I know that this could be taken wrongly, but I think there's a risk any time that the original intent of the text is violated. David was a man of war. He made threats, and would carry them out. When he threatened someone, it was with the intent of terrifying them, not just with their death, but with the death of everyone in their village.
Similarly, the nature of the oath was to put each at the other's total mercy. The euphemism, "under the thigh" gives no hint of how vulnerable the parties made themselves.
In many of the newer versions, the prohibitions against homosexuality are left out, and covered with euphemisms of "sexual immorality." In the NIV, Mark 16:9-20 are completely omitted, I believe, on rather shaky grounds that they do not appear in two trustworthy manuscripts of the NT, although they appear in many others, some considered as trustworthy as the texts that omit the verses. I believe this was a political decision, as it includes the verse "they will pick up serpents and if they drink any deadly poison, it will not harm them; they will lay hands on the sick, and they will recover."
There is a strong movement to try and make Jesus into just another teacher, who was not the Son of God, and did not claim to be. The modern church shies away from supernaturalism, and I believe these verses were excluded for political, rather than textual reasons.
Just my 2 cents