Leaving a Legacy on the Future

After spending much of his 20's and 30's scouring the dating pool for a mate, William Smith is now well into his 40's and feels that he's running out of time to find a mate to start a family. Therefore, at the tail end of the 2020's and his 40's, Mr. Smith decides to try to help infertile couples conceive via invitro-fertilization and that, in turn, allows him to have his own biological offspring and "leave a lasting legacy", on the future, which he ends up meeting; starting in 2029; the year he turns 50 years old, and lasting well into the 2030's with each open sperm donation he makes.