The exponent of the RSA public key must be odd.??

[Luis Saiz]

OS/390 Integrated Cryptographic Service Facility Application
Programmer's Guide Version 2 Release 5 Publication No. SC23-3976-02 :
 http://ppdbooks.pok.ibm.com:80/cgi-bin/bookmgr/bookmgr.cmd/DOCNUM/SC23-3976/CCONTENTS



In several parts of the document it's specified that, as a restriction:


> The exponent of the RSA public key must be odd.
>
It's there any (unknown to me) security reason to be this way, or it´s
an implementation/standard option??