Who first realised that ideas have sex?

These days, "ideas having sex" has been popularised, but it wasn't always so. I've been looking at which cultural evolution pioneers realised that ideas have sex. Some of the earliest references I found were:

• 1970 - Jacques Monod, in the book Chance and Necessity wrote: "For a biologist it is tempting to draw a parallel between the evolution of ideas and that of the biosphere. For while the abstract kingdom stands at a yet greater distance above the biosphere than the latter does above the nonliving universe, ideas have retained some of the properties of organisms. Like them, they tend to perpetuate their structure and to breed; they too can fuse, recombine, segregate their content; indeed they too can evolve, and in this evolution selection must surely play an important role."
• 1987 - K. Eric Drexler - Engines of Creation: The Coming Era of Nanotechnology "Like genes, ideas split, combine, and take multiple forms (genes can be transcribed from DNA to RNA and back again; ideas can be translated from language to language)"- page 30.
• 1989 - Lynch et al A model of cultural evolution of chaffinch song derived with the meme concept covered the concept.

In the 1990s, the idea became more common - appearing explicitly in Lynch's Thought Contagion (1996), for example. However, I didn't find too many other mentions of sexual recombination of ideas in the 1970s and 1980s. The idea doesn't seem to be present in Dawkins 1976, 1982 or 1986. Indeed in 2005 (page 192), Dawkins wrote:

One respect in which [memes] are not like genes is that there is nothing obviously corresponding to chromosomes or loci or alleles or sexual recombination.

...suggesting that he hadn't grasped the concept of sexual recombination among ideas then.

The idea isn't in Cavalli-Sforza & Feldman (1981), it isn't in Lumsden & Wilson (1981) and it isn't in Boyd & Richerson (1985). The latter do mention "cultural mating" - but they use the term to refer to individuals acquiring ideas from multiple parents - and not "ideas having sex". I didn't see it in Hull (1988), Brodie (1995) or Boyd & Richerson (2005) either.

Darwin (1871) gave us:

Languages, like organic beings, can be classed in groups under groups; and they can be classed either naturally according to descent, or artificially by other characters. Dominant languages and dialects spread widely, and lead to the gradual extinction of other tongues. A language, like a species, when once extinct, never, as Sir C. Lyell remarks, reappears. The same language never has two birth-places. Distinct languages may be crossed or blended together.

...though that isn't quite the same. Words having sex would have captured the idea.

Recombination is a fairly fundamental evolutionary idea - but it apparently took a while to sink in - in the domain of cultural evolution.