'Libertine bubbles'

Ain't nobody here but us Scyllarides latus larvae

Stranger and more plausible than the theory (attributed to Aristophanes in the Symposium) that sex has its origins in people chasing around trying to find the other half from which they were once severed is the libertine bubble theory of Thierry Lodé, which argues that rather than providing reproductive advantages:

it might be better to see sex as a genetic exchange between two organisms, as originating from an archaic horizontal gene transfer process among the prebiotic bubbles on the ocean surface, which are thought to have played a major role in the creation of living cells. My theory suggests sex results from three key primitive conditions: first, bubbles form spontaneously, creating a favourable environment for genetic material; second, the "promiscuous" nature of these bubbles allows transfer of genetic material among the most "libertine" of the bubbles, gradually leading to a certain membrane selectivity; and third, DNA overcrowding encourages primitive meiotic recombination.