* Finally fertile *

While the bar patron savoured a double martini, an attractive women sat down next to him.
The bartender served her a glass of orange juice, and the man turned to her and said, "This is a special day. I'm celebrating".
"I'm celebrating, too," she replied, clinking glasses with him.
"What are you celebrating ?" he asked.
"For years I've been trying to have a child", she answered, "Today my gynaecologist told me I'm pregnant !"
"Congratulations", the man said, lifting his glass. "As it happens, I'm a chicken farmer, and for years all my hens were infertile. But today they're finally fertile".
"How did it happen ?"
"I switched cocks".
"What a coincidence", she said, smiling.