Races from the original Star Trek such as the Romulans, Klingons and Vulcans have played roles of varying importance in the series.
Vulcans have the same emotions as humans, but over the centuries have learned to suppress them to attain a state of logical thinking and action.
In essence, Vulcans are unable to feel emotions such as love, hate, happiness or jealousy.
Since Vulcans' philosophy is to prize the rational over the emotional, that means suppressing the human emotions he inherited from his mother.
Vulcans often claim that they have no emotions, being creatures of pure rationality, but that is, of course, impossible, rational thought being an evolutionary offshoot of emotions, which underlie thought.