# [Jelly][1], 13 [bytes][2]

    Œlf“aeiou”L%2

All test cases are at **[TryItOnline][3]**

How?

    Œlf“aeiou”L%2 - Main link takes an argument - s
    Œl            - lowercase(s)
       “aeiou”    - string of lowercase vowels
      f           - filter - keep only the vowels
              L   - length - the number of vowels
               %2 - modulo 2
      
---
**Non-competing, 6 bytes** (since I just added the function `Øc`)

    fØcL%2

Test cases also at **[TryItOnline][4]**

Same as above, but `Øc` yields the English vowels, `'AEIOUaeiou'`


  [1]: https://github.com/DennisMitchell/jelly
  [2]: https://github.com/DennisMitchell/jelly/wiki/Code-page
  [3]: http://jelly.tryitonline.net/#code=xZJsZuKAnGFlaW914oCdTCUyCsW8w4figqxL4oKsWQ&input=&args=InRyZWVzIiwiYnJ1c2giLCJDQXRzIiwiU2F2b2llIiwicmh5dGhtIg
  [4]: http://jelly.tryitonline.net/#code=ZsOYY0wlMgrFvMOH4oKsS-KCrFk&input=&args=InRyZWVzIiwiYnJ1c2giLCJDQXRzIiwiU2F2b2llIiwicmh5dGhtIg