Lee Irons is leading the charge for the eternal generation of the Son based on the traditional rendering of monogenes (μονογενής) as "only-begotten". Lee is a fine scholar, so he's a good spokesman for that position.
The word occurs in Jn 1:14,18; 3:16,18 & 1 Jn 4:9. And that understanding was codified in the Nicene Creed.
I've already explained my own position. I affirm eternal Sonship but deny eternal generation:
But now I'd like to raise a linguistic issue. Monogenes is a compound word. Sometimes the meaning of a compound word is a combination of what the constituent words individually mean. And that's the unquestioned assumption or inference when monogenes is rendered "only-begotten". Proponents of eternal generation justify their position on the supposition that monogenes has the conjoined meaning of the two individual words that compose it.
Put another way, they presume the compound word has a transparent meaning, by combining what each of the two words mean. And certainly the import of many compound words follows that simple additive principle. To take a few English examples: bedtime, dishwasher, football, footpath, headache, headlight, northwest, rowboat, shortsighted, taillight, teapot, toothbrush.
In cases like that, if you know the meaning of the uncompounded words, you can figure out the meaning of the compound word.
But many times, a compound word has an idiomatic meaning that's not derivable from the conjoined import of the uncompounded words that compose it. To take a few English examples: acidhead, callgirl, cottonmouth, cyberspace, dot.com, flying saucer, grease monkey, greenhouse, homesick, hotdog, jailbird, kickback, ladybug, soap opera.
(In English, a compound word can be solid, hyphenated, or open.)
You can't tell what these words mean by simply combining the individual import of each word.
To take an analogous example, compare these two sentences:
Luigi is waiting for the coin to drop
Let's drop the dime on Luigi
To someone who doesn't know English well, these seem to be semantically equivalent phrases, but of course, they are completely different.
Given that compound words can have, and often do have, idiomatic meanings (and I believe that holds true for Greek as well as English), are proponents of eternal generation justified in simply assuming that monogenes has a transparent meaning–or is that unwarranted unless they present an argument to exclude the real possibility that it's idiomatic?