Can't Find This TV Episode

When I was very young I watched an episode of a TV show with a sort of sci-fi plot. I think it was made in the 1950s or early 60s. Ten or Fifteen years ago, I used Google to find it and watched it again. But now, when I try, I find nothing. Here is the plot. Can anyone tell me what this was? My description may be wrong in some detail, but is basically correct.

I had thought this was "Alfred Hitchcock Presents." A woman anthropologist and her male partner have been investigating some very primitive tribe. The tribe has an hallucinogenic drug that they believe induces true visions of the future. The anthropologists have decided that the woman will try the drug, in her apartment, I believe, with her male colleague standing by to act if something goes wrong.

She takes the drug and finds herself in a distant future in which there are only women - no men at all. They have some medical procedure for producing children. Apparently, some biologist in her time, more or less, had been experimenting with a virus and it escaped and killed all men, but she doesn't know that yet.

She is in a time in which this all happened long ago and basically, no ordinary person is even aware that there used to be two genders. She tries to ask them what happened to all the men, but the women are horrified at her insane statement that there used to be another gender. They finally take her to an historian who is a very old woman. The historian knows exactly what she's talking about. As I recall, the historian's grandmother had even, wistfully, described men to her when she was a little girl. She explains to the anthropologist about the virus.

At some point she wakes up from the trance and is absolutely convinced it was real. Her colleague tries to tell her that it was just a drug induced hallucination, but she is completely convinced that it was real and can't be persuaded otherwise. He tries to prove to her that she's wrong by looking up the biologist who created the virus in the phone book. Apparently, he lived in her town and had an unusual name. There is such a name in the book.

She finds the biologist and shoots him to death. When she is awaiting trial, her colleague comes to her jail cell and tells her that the biologist had a son with the same name who has vowed to carry on his father's research.

Now, Googling, I can find no sign of it. Has anybody seen it?