The OT says Jacob was 83 years old when his sexual adventures in Paddanaram began. It is asking just a little too much to expect critical readers to believe that an 83-year-old man could have been capable of such sexual vigor while working long hours in the day tending to large flocks of sheep and goats.
Jacob was certainly not alone tending sheeps and goats; Laban was a wealthy tribal chieftain whose household would have included vast numbers of servants. Furthermore, a modern person with a desk job has no place to speak of the capability of ancient persons -- or of any person, for that matter.
Is this possible for a man ages 83-96? Ask Jack LaLanne, aged 94 in 2009. Ask "Banana George" Blair, the 94-year-old barefoot water ski maniac who wanted to compete in the Olympics and was still touring the world in his 80s. Just because a critic isn't pulling one-ton boats with his teeth, or tending sheep or what have you, doesn't mean others in his age group don't. Jacob's life was far from as hard as these chaps put on themselves -- and he lived in an era when only the strong survived.
What of Jacob being 83? Skeptic X offers a litany of calculations, and says:
Egyptian records of the period indicate that 110 was an ideal age to live to; 140 would have been above-ideal, then, but obviously not considered impossible or odd. As for being more vigorous, a round of about a dozen sexual encounters over twenty years would not suggest to me a requirement for excessive vigor; without getting into too much detail, there are certainly elderly men today (with their young "charges") who might give critics a lesson or two in vigor, and that's sure easier than pulling boats with your teeth through freezing water.
Moreover, while women may be past an age of childbearing, it is a matter of medical record that men can remain fertile. A source now offline reported of certain people (now deceased, but at the time this was originally written, still alive):
"Captain Kirk's amiable engineering chief Scotty (less well known as actor James Doohan) is to become a father again at the age of 80...Nobel prize-winning novelist Saul Bellow recently became a father at the age of 84...The oldest father on record is Les Colley, an Australian who died in 1998. His last son was born when he was 92, though there was a subsequent row over the boy's parentage...[another source gave Colley's age at the time as 93 years, 10 months] But the most impressive achievement has to be that of actor Anthony Quinn, famed for his lusty performance in the film version of Zorba the Greek, who became a father again at the age of 81 in 1996 - for the 13th time."
Abraham made a statement which plainly indicated that even in biblical times it was considered unlikely that a man in his nineties could sire children.
Abraham's statement says nothing about his age being a factor in and of itself. The statement is made with reference to the fact that Abraham, now being near 100, had been unable in the past 70-80 years not produced children. This was, in his mind, obvious evidence of infertility of some sort which was permanent. The reply is essentially, "After all these years of failure will my dream now come true?"
Just before the story of Jacob's deception of Isaac was told in Genesis 27, the 26th chapter ended by saying that "when Esau was forty years old," he married two Hittite women. If Esau was 40 at this time, then Jacob was the same age, because they were twin brothers. After saying this about Esau, the very next verse in the Genesis narrative begins to tell the story of Jacob's trickery in getting Isaac to bless him. That story runs throughout the 27th chapter and ends by telling of Rachel's fear that Esau might kill Jacob for his duplicity. Pretending then to Isaac that she was afraid Jacob might do as his brother Esau had done and marry a Hittite woman, Rachel used this as an excuse to urge Isaac to send Jacob to Paddanaram. Surely, then, thirty-six years had not passed since Esau had married his Hittite wives. How convincing would her fear have been to Isaac if Rachel had reached back thirty-six years for something to express concern about?
One fails to see why the 36 years ought have made a difference. Neither Jacob nor Esau had very wide choices for marriage, and 36 more years would not have served much for broadening the field.
Gen. 28:6-9 says, Now Esau saw that Isaac had blessed Jacob and sent him away to Paddan-aram to take a wife from there, and that as he blessed him he charged him, "You shall not marry one of the Canaanite women," and that Jacob had obeyed his father and his mother and gone to Paddan-aram. So when Esau saw that the Canaanite women did not please his father Isaac, Esau went to Ishmael and took Mahalath daughter of Abraham's son Ishmael, and sister of Nebaloth, to be his wife in addition to the wives he had (Gen. 28:6-9, NRSV).
To believe that Jacob was 76 when he went to Paddanaram, as chronological information cited earlier indicates, requires us to believe that Esau was married to his Hittite wives for thirty-six years before he realized that 'the Canaanite women did not please his father Isaac.' That, of course, is ridiculous, because recognizing that one's parents are dissatisfied with his choice of a wife would typically occur much sooner than that.
It probably did, but the word for "seeing" is ra'ah, which has varied meanings of seeing, discerning, and taking heed. The word is used to note that Esau reacted at this point to Isaac's displeasure, not to say that he never, ever noted the displeasure before. (Indeed, 26:35 already says that the women were a "grief" unto Isaac.
To say that Jacob was 76 when he left for Paddanaram requires one to believe that 36 years in his life were skipped in the Genesis narrative. The writer detailed Jacob's life more specifically than any other Genesis character, including even Abraham, yet he passed over entirely 36 years of this central character's life, from age 40 to 76, if Jacob was indeed 76 when he went to Paddanaram. That seems very unlikely.
Why is this unlikely? The core of this objection lies in the assumption that during those 36 years, Jacob had done something worth mentioning. These records were written at a time when few could read and paper was scarce and expensive, and when oral memory was best preserved for events of significance; no one wanted to hear about, or cared about, the day Jacob trimmed his toenails.