OK I was brave/odd enough to googe and found this
Apparently, your friends have stumbled upon one of the eternal mysteries of the human body. After reviewing some theories on why pubic hair exists, it appears there's no definitive answer. It seems as though the prevailing theory relates to pheromones ? scents that the body produces that can be sexually stimulating to others.
It's thought that the tufts of hair that grow around the genitals, as well as under the arms, capture these erotic scents. Pheromones get trapped in the pubic 'do when apocrine glands release an odorless secretion on the surface of the skin that combines with bacteria decomposed by the secretions of the sebaceous glands. Believe it or not, humans have the same number of hair follicles as apes, except our body hair is generally very fine or barely visible in comparison. So, while pubic hair and underarm hair might be considered the primary scent traps, they're by no means the only ones. For some people, scents from these areas are noticeable and consciously increase sexual arousal. For others, pheromones might not be obvious but may be detected subconsciously.
A few hypotheses also exist about why we have hair on our pubic places. Some people believe that it keeps our genitals warm. In prehistoric times, when only a loincloth was worn to cover the penis or vulva, this might have held true. However, the idea that a pubic mane exists for warmth doesn't make much sense in today's world since our genitals are kept toasty by clothing. In order for this theory to be true, it would seem that our bodies would probably have evolved to the point where we would have lost the need for pubic hair, which is not the case. Also, if it were intended for generating heat, wouldn't we have much more pubic hair? If this were so, men would probably have hair on the shaft of their penis and more hair on the scrotum to insulate the testicles; women would have hair on the skin of their lower torso to insulate the internal reproductive organs. Others believe that the purpose of women's pubic tresses is similar to that of cilia in the nose (a.k.a., nose hair), in that it prevents dirt from entering the vagina. Okay, this makes some sense... but why wouldn't men have similar protective locks around the opening of their urethra?
Other theories regarding the purpose of pubic hair probably exist, but currently, the pheromone theory seems to be the most logical. As far as non-functional use goes, pubic hair can be decorative or attractive to their owners or to others. Some of the related Q&As below explore the many aesthetic possibilities of pubic hairdos.
For more information about pheromones and their effect(s) on sexuality, look for James Vaughn Kohl and Robert T. Francoeur's book, The Scent of Eros: Mysteries of Odor in Human Sexuality.
From go Ask Alice. Well now I know what to say when my y10s ask me