Blood in the semen can be caused by benign and malignant disorders of the prostate gland, seminal vesicles, spermatic cord, and ejaculatory duct system; urogenital infections; metastatic cancers; and vascular disorders. It normally resolves on its own, but should be evaluated.
Semen can change color for several different reasons. The yellow jelly-like substance that is part of the ejaculation is the sperm contained in that ejaculation. The white/cream color is seminal fluid produced to help with ejaculating the sperm through the testicles into the tubing that carries it through the penis. SO, the more yellow the ejaculation the more sperm are present. Thats why if we masturbate or have sexual release alot our ejaculations are more white/cream colored. Some foods and drinking more water can alter the consistency and color to some degree. So, be glad that the yellow is there, especially if you want to be a father!
Hopefully you guys found this little tidbit of info very valuable....lol