Don't know anything about RNA, but I wonder if some kind of small virus could be used to test the micro RNA transport hypothesis. Googling "micro RNA virus", first link is
https://www.ncbi.nlm.nih.gov/pubmed/21431678 . The paper seems promising, since 2004, more than 200 microRNAs (miRNAs) have been discovered in double-stranded DNA viruses, mainly herpesviruses and polyomaviruses.This chapter aims to summarize our current knowledge of viral miRNAs, their targets and function, and the challenges lying ahead to decipher their role in viral biology.
Using microRNA virus to test the sperm transport mechanism seems to be a good idea.
Glooging for "microRNA virus sperm transport" suggest the link: Intercellular Transport of MicroRNAs (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3580056/), This review brings into focus what is currently known and outstanding in a novel field of study with applicability to cardiovascular disease.
So, perhaps sperm transport of microRNA could be tested using some RNAvirus to produce cardiovascular desease.