In Genesis chpt 12&20

In Genesis chapters 12 and 20 Abraham passes his wife Sarah off as his sister to keep from being killed. Supposedly, she was so beautiful that the kings in each of these stories might have him killed in order to claim Sarah as their own. In ch. 12 Sarah would have been at least 65yrs old and in ch. 20 she would have been closer to 90yrs. Question..... why would any king have been attracted to women of this age when they could have any woman that they wanted? Is the writer trying to tell us something about Abraham?
The question Is quite astute, and I must admit that I have pondered it myself since reading the text. She may well have been still "beautiful" in her mid 60's but it is highly unlikely that she would have been physically attractive enough at 90ish to attract the attentions of a Philistine King. Who, in reality was probably more likely to be enjoying the pleasures of nubile maidens.The writer(s) must have known that the statements would prove incredulous to readers. They must have had a reason for doing so. I think the story is more about Abimelech and his ability to receive communication/warning from god. The incident seems to reflect a form of universalism in that God is shown deference and respect by a gentile and God in turns seeks to warn and protect a non Hebrew. Maybe even to illustrate that God had adherents everywhere. As I sit here writing this I don't know if I can recall God speaking to gentiles elsewhere in scripture. And, certainly not often to gentiles so vilified as the Philistines.The initial writing in chapter 12 may be there in order to make the Israelites feel better about their wives, daughters, and sisters being taken from them, raped, and/or enslaved by consecutive armies of conquerors. It would be easier to watch those they loved used and abused if they had known that Abraham had allowed the same thing to happen just to save his own hide.I read somewhere once that the reason "Jewishness" is passed down the female line instead of the male was that so many conquering armies swept through the Levant killing the men and raping the woman that the only way they could survive as a people was to adapt to the realities of the situation.