We know that Klingon and Human DNA is compatible enough to reproduce (B'Elana Torres); same with Human and Vulcan DNA (Spock), and Cardassian and Bajoran DNA (Tora Ziyal).
Are there any examples of 2 humanoid species in Star Trek that are explicitly noted in canon as NOT being biologically compatible? (unable to produce a viable genetic offspring between each other with technological assistance as well)?