Sentence:  [I]n controlled studies some men have been observed to <WSD>ejaculate</WSD> but not have orgasm or have orgasm but are unable to <WSD>ejaculate</WSD>. 
Meaning of the word marked with <WSD> tags:  Of a human being or other mammal: to forcibly eject from the urethra in response to sexual stimulation, in a male, semen; and, in a female, vaginal fluid.