“Where are the parents” - I will point out that half of Gen-Z / Zoomers are currently 17 or older and the oldest ones are 26. Even among the ones which are still minors, some of them have parents who are willing to allow a great deal of freedom in regards to exploring personal identities, it’s not strictly divided between “controlling” and “neglectful” like you seem to be suggesting. Also, I don’t know what stats you’re using, but the recent Gallup poll put it at 5.6% gay / lesbian, 13.1% bisexual, 1.5% other (“Other” includes asexuals, and it’s not clear how many pansexuals chose “other” rather than bisexual) for Gen-Z. There’s also the matter that Gallup may not have polled very many people under 18 (it doesn’t say), rendering the parent thing largely moot. It also didn’t say anything about how many specifically identify as straight. I’m going to assume that if only ~44% 48% identified as straight in some other source, then the remaining ~36% 32% are mostly “not sure” with maybe a bit of heteroflexible thrown in. I mean, while half of them are adults or nearly so, the other half are teenagers and kids, and they don’t always completely know themselves. (Assuming that a significant number of under-18s were polled by this alternate source, which I have no way of knowing.)
Alternately you read the stat that 62% of LGBTQIA+ people identify as bisexual, rounded it off to 60 (and rounded 5.6 to 6), subtracted 100% - 60% - 6% = 44%, in which case your math is wrong because it actually equals 34%. Also that’s mixing different kinds of stats, which is a no-no. I mean, I hope it’s not something really stupid like that, but I wouldn’t be surprised.
[Edit: I messed up, it’s “48% identify as straight”, the 44% refers to something else. Ignore my entire last paragraph. It might still be bad math though.]