Uegis is right, once again. I went to UCD and from what I have been told, the double major is usually granted to someone getting a BA and BS but for two BS degrees, I don't think they will do it.
I was a BioSci major at UCD and when I considered going back for a second baccalaureate, the only options for me were non-science bachelor's because I already had a BS.
Honestly, I'd say that while having the two degrees certainly won't hurt, I wouldn't say it would help any more than going out and volunteering or getting some 'life experiences' under your belt. I was only a foreign language requirement away from getting my second major in Political Science but the College of Letters and Science kicked me out when I reached the 225 unit limit, so that's another consideration. Because my primary major was nearly complete, they said that the second major was less critical and in the interest of getting my butt out of there, I didn't finish it.
It is possible to have an area of interest outside your major and not get a second degree in it. If you really feel like you need the second degree, get a minor in BioSci.