Pay someone else to do it. I'd never have love with my grandmother, on any terms.
"This could be a pre-destination paradox... I could be destined to fall in love with that woman and become my own great-grandfather."
You're being ridiculous.
"Ridiculous? If I don't meet with her tomorrow I may never be born!... You saw the way she looked at me. You can't just dismiss this."
I can sure try.
"All right - fine! But I can't wait to get back to Deep Space Nine and see your face when you find out that I never existed!"
- Dr. Julian Bashir to Miles O'Brien on an encounter with what may have been his Great-Grandmother on the original USS Enterprise Turbolifts.