I just so happened to read an excellent article about this very subject today.

Here is a VERY detailed paper (168 pages with references) by researchers with 26 years of research data on the subject.

http://www.tpwd.state.tx.us/publications/pwdpubs/media/pwd_rp_w7000_0827.pdf

You should read the entire article, but my conclusion is that if you want your deer to have larger horns you should shoot spikes.

FWIW, Nathan