If you have access to the actual research paper as well as the other two scientific studies, you will see that the researchers goes on to describe the sperm that they found to be LESS THAN THAT OF AN INFERTILE man. And further more, the sperm showed very little forwards motion. For all practical purposes, they were dead.
A man ejacu;lating less than 40 millionnormal motile and healyhy sperm are officially infertile. It is unreasonable to base a whole life philosophy and outlook on less than a million half dead sperm with very little forwards motion.
The source of sperm in pre-ejaculate fluid is not because there are sperm in pre-ejaculate fluid. It is left over sperm from a previous ejaculation that is left over in the urethra. The longer ago that was, the more dead these sperm are. A urination after a previous ejaculation will also clean the urethra and kill the left over sperm. The few hundred left over after that cannot find their way anywhere.
Pre-ejaculate is dangerous for other reasons. It is normally a sign that the couple is engaging in unprotected sex. With many men not being able to fully control ejaculation, this is indeed a very dangerous situation over which the woman have no control. And she will end up with the mess.
Perfect use of the withdrawal method approach the failure rate of condoms, around 3% to 5%. This shows that education around pre-ejaculate is totally misplaced. It is not the pre-ejaculate that is dangerous. It is the fact that the couple is having unprotected sex. They are often very young and the male partner have very little control over his ejaculation in his early and mid teen years.
If a condom slips, the chances are also very good that the few drops of pre-ejaculate in the tip will just stay right there and not leak out. Even when a condom breaks, the penis head will go through the side of the condon and the tip will stay intact. After ejaculation this changes as the semen will very likely be all over the penis head and leak out.
Added to all this is the fact that a woman needs to be in her fertile week, and that only one in three women with a full ejaculation right in their period will end up pregnant. So the chances are, for all practical purposes as close to zero as it can get that she can be pregnant.