When DNA is introduced to polycations (valency ≥ +3), it spontaneously condenses in vitro, a process driven by electrostatic interactions between positively charged polycations and the negatively charged phosphate backbone of DNA. It has been established that DNA condensation occurs when approximately 90% of the DNA charge is neutralized by the condensing agent. In our study, before assessing damage, we initially characterized the DNA precipitation behavior with each polycation. Figure illustrates that DNA precipitation, as a function of the N/P charge ratio, depends on the length, or equivalently, the charge of the polycation. For the longest polycations used in this study, salmon protamine, polyR, and polyK, DNA precipitation occurs in a continuous manner upon addition of the peptide. For example, at N/P 0.5, where sufficient polycation is added to charge compensate 50% of the DNA phosphates, we see 50% of the total DNA condensed for these three systems. At N/P ~1, where there are sufficient cation amines to fully compensate for DNA phosphate charges, salmon protamine, polyR, and polyK all fully condense DNA. Decreasing the polycation length affects DNA precipitation. We studied triarginine (R3) and two hexaarginine peptides (R6 and R3pSR3), chosen as protamine mimics, to explore the potential effects of residual phosphates on sperm chromatin. Compared to longer polycations, the two hexaarginine peptides condensed less total DNA for a given N/P ratio. For example, at N/P 0.5 and 1, only approximately 20% and 60% of total DNA were precipitated. Interestingly, the presence of the phosphate did not significantly alter the DNA precipitation behavior in the hexaarginine peptides, although it had a substantial impact on the resulting DNA packaging density. Complete condensation by these two peptides only occurs at N/P charge ratios >1.5. The precipitation behavior of R3 is very different. As shown in Figure , DNA precipitation by R3 does not occur below a critical polycation concentration. Only above this concentration does DNA precipitation take place, consistent with previous studies on trivalent cations such as cobalt hexammine and spermidine. For example, Raspaud et. al.