These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fridge Brilliance - The idea to mix sperm to get the perfect man is, of course, ridiculous. Of course, since one of their fathers looks a lot like Julius, you have to wonder if Traven didn't add a bit of his own "genetic material", resulting in Vince, making them, technically twin half-brothers, which is not unheard of.
Mixing sperm together doesn't somehow cause genes to get swapped, but the resulting chemical warfare among the sperm competing for fertilization does bias the child toward being more effective at reproducing.
Ho Yay / Incest Subtext / Twincest - Believe it or not. Julius is a bit overly loving toward Vincent, Vincent doesn't mind after the first five minutes, the two get along almost perfectly, dance together with no though, hug constantly...
True fact: Twins have a strong tendency to touch one another more than untwinned siblings, with no sexual connotation. Untwinned persons tend to see it as sexualized because they have no frame of reference.