“Those yogis who abstain willfully from sex and cultivate jhana are born in Brahma realms. Those Brahmas cannot engage in sex either. They don’t even have sex organs.”
That alone, abstaining from lust of flesh in the sphere odf body alone, would neither lead to Brahmas not open up Jhanas, good householder.
Even for the gain of the Brahmas Methuna-Dhamma has deep levels where there needs to be refrain.
(Samana Johann)