The Borg poo-pooed single cell insemination.
Too much effort for not enough result.
What should happen is that Seven should be compelled to buy a bikini, then visit several beaches and public swimming pools wearing those two thin strips of barelycoveranythings while farting nanoprobes everywhere submersibly... And Starfleet Intelegence will never suspect her, because it's a scientific fact that pretty girls don't fart.