Our study is the first to show data on male adolescents’ attitudes and risky behaviours in a Southern Italian region (Calabria). The results demonstrate that their consumption of cannabis and alcohol is lower compared to that of their peers living in Central or Northern Italian regions. Moreover, we found out that most of these adolescents receive information on sexuality and STIs mainly from the internet and friends and that a good knowledge of STIs was, surprisingly, associated with a habit to not use contraceptive methods.

It is well known that adolescence is associated with high levels of alcohol binge drinking because it encourages the initiation of sexual activity by lowering anxiety and inhibitions [18]. Unfortunately, chronic alcohol consumption is also associated with the appearance of sexual dysfunction, such as the loss of libido, premature ejaculation, and erectile dysfunction [19]. Adolescents also admit to the regular use of cannabis and other illicit drugs, risky behaviours that expose them to potential future sexual disturbances and diseases [20]. In addition, consumption of these substances is often continued throughout their adult lives, with further negative consequences on sexuality and fertility [9].

In contrast with our results, Gianfrilli et al. have recently reported that in several Northern and Central Italian regions, just one over half (51%) of the subjects examined admitted to being regular cigarette smokers. Even the percentages related to occasional alcohol consumption (80%) and heavy drinking habits (30%) were much higher when compared to the results of our study [21]. One point in common with Gianfrilli’s study is that adolescents try illegal drugs, especially marijuana/hashish, at an early age. Cigarette smokers are also equally represented in all Italian regions. The consumption of alcohol (per weekend = 9.3%) and cannabis (least once-a-week = 21%) were lower in Southern regions than in Northern ones. Interestingly, we observed that the use of alcohol and cannabis among adolescents in Southern regions is often combined. This finding had already been reported by other authors in a survey conducted on young people ages 13 to 19 [22].

Luckily, recent studies have demonstrated that, since the early 2000s, the consumption of tobacco, alcohol, and cannabis among adolescents is decreasing both in Europe and North America [23,24]. In fact, the International Health Behaviour in School-aged Children (HBSC) study showed that the percentage of 15 year old smokers in Europe and North America decreased from 24% in 2002 to 12% in 2014. Weekly alcohol consumption decreased from 29% to 13%, and, finally, the habit of cannabis smoking among 15 year old boys decreased from 22% to 15% [25,26]. These changes may be due to a sharp drop in face-to-face peer contacts that yielded an increased use of electronic media communications [27]. The results of the studies conducted in Northern, Central, and Southern Italian regions are in contrast with these findings and, therefore, suggest that Italian adolescents need more information and awareness about the dangers of risky behaviours. Thus, it is advisable to promote a series of robust campaigns in Italian regions aimed at changing the attitudes of adolescents regarding the excessive use of tobacco/marijuana.

Gianfrilli et al. showed that 60.3% of adolescents engage in regular sexual activity and, among them, 41% have unprotected sex [21]. Our results highlight a discrepancy between the belief that adolescents have good knowledge of the risks related to unprotected sex and their habit not to use condoms, even with different partners. Indeed, although about 70% of the respondents declared to know about STIs, we observed that 25.6% of students examined used contraceptive “sometimes” and that the 20.9% of them used contraceptives “never”. These findings are in line with reported data in the literature. The survey conducted by Drago et al. on 2867 Italian adolescents, which aimed to investigate knowledge about sexuality, revealed that 22% of the interviewees knew that condoms are the only contraceptive means for preventing STIs, and just 0.5% have recognized sexual diseases on the list provided [11]. Similar results have been reported by Bergamini et al, whose study pointed out the need to improve teenagers’ awareness of risky behaviours for the prevention of STIs. In their opinion, school should play a crucial role in the reinforcement of sexual educational programs [28]. The survey of Wand et al., carried out on a sample of 16–29 year old subjects, demonstrated that the majority of high risk sexual behaviours and STI diagnoses were associated with the consumption of illicit drugs and alcohol. In conclusion, the diffusion of STIs could be prevented by mitigating high risky sexual behaviours among teenagers [29].

As we have already stated before, another risky behaviour among adolescents is represented by their attitude to have unprotected sexual intercourse. This dangerous habit predisposes male adolescents to the development of male accessory gland infections (MAGI), including prostatitis, vesiculitis, and/or epididymitis. Several kinds of microorganisms are involved in the etiology of MAGI, such as Escherichia coli, Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, and other mycoplasmas, Candida albicans, Trichomonas vaginalis, and HPV [30]. We believe that a good information campaign is necessary both for families and adolescents, to contrast problematic habits in sexual intercourse. It is also advisable that HPV vaccination in 11 year old boys become mandatory in order to prevent the spread of STIs and other diseases not directly related to HPV. This new practice would likely contribute to a sharp reduction in the chronic, often asymptomatic, damage responsible for apparently idiopathic sperm abnormalities. Asymptomatic or pauci-symptomatic forms can lead to chronic inflammatory processes, responsible for the development of hypertrophic-congestive and fibro-sclerotic ultrasound-evidenced variants. These forms differently impact sperm quality, sometimes irreversibly [19]. They also may contribute to sexual dysfunction, such premature ejaculation [31].

In general, although the attitudes and sexual behaviours of the population have radically changed, adolescents usually approach sexuality unprepared and uninformed, especially when they live in underdeveloped socio-economic and cultural contexts. In addition, as we have already discussed, a high percentage of teenagers learn about these issues on the internet and compare what they know with their friends [32]. Unfortunately, the internet is just a container of general (and sometimes incorrect) information, ranging from pornography to (un)controlled medical indications that cannot provide the web-surfer with adequate interpretative tools. Several studies have shown that interpersonal relationships are the primary elements in the decision-making of adolescents in risky sexual behaviours and that peers are more important than adults in defining norms and attitudes [10,33].

We are aware that the limitations of the present study are related to the lack of data on testicular volume, sperm parameters and sexual function. We also recognize that a multicenter prospective study should be carried out to assess the impact of risky health behaviours on sexuality and fertility per year of exposure, starting from adolescence. However, we have to point out that this study, which is unique and relevant because of the novelty of its results, represents a different approach compared to previous epidemiological data coming from prevention campaigns in Calabrian areas.