Theoretical question regarding transmission

I had this thought the other day when I was reading an article about a new HIV vaccine being developed in Canada. I asked myself, does the presence of semen increase the MALES risk for transmission during heterosexual intercourse?

For instance:

A HIV negative male has sex with an HIV positive female without a condom. If his risk for infection were, say, 1 in 1000 if he didn't ejaculate, if he indeed DOES ejaculate inside the female, does his chances of contracting the disease go up? (i.e. Does the presence of semen increase his risk?) Or does male ejaculation and the presence of the males own semen not affect the odds of transmission from female to male during heterosexual sex?

Just curious since I read that proteins in semen have been found to increase risk

[RainLover71]

It wouldn't make any difference and a risk is a risk no matter what kind of odds you place on it.Safe sex is the best way to go in this situation as you already know.

[Teak]

HIV is transmitted by;
Unprotected penetrative anal and/or vaginal sex
Sharing works with other IV drug abusers
Mother to child