IN FOCUS
Evidence, Echoes, Effects
Editor: Federica Esposito
As interns at CUE, on March 4th, we had the opportunity to attend an insightful lecture at the University of Amsterdam (UvA), held by psychologist and sexologist Sanderijn van de Doef, whose work focuses on sexuality education and the sexual development of young people. Sanderijn also advises the development of CUE’s Transition Into College Dating Life series.
The lecture concentrated on the development of sexual behaviour among young people in the Netherlands, and on the relationship between young people and sexuality. The speech started with addressing the relationship between babies and sexuality: although sexuality is commonly associated with teenage years, one’s relationship with their own sexuality begins in the first years of life. In fact, sexual development is part of growing up right from early childhood. It shows in multiple ways, but one of the primary means by which this is demonstrated is through sexual play. It is through this sexual play that children begin to express their relationship with their own bodies and those of others, including the genital area. Therefore, as educators and caregivers, it is fundamental to understand the crucial role consent plays even in these early stages – in relation to others, to oneself and to the educational process. Even at this age, precious educational opportunities can arise to introduce the concept of consent and its importance to the individual.
Sanderijn delivered a lecture at the University of Amsterdam on March 4th, 2026
Sanderijn explained how sexual play can develop from 2 years old, and individual genital stimulation can play a role even before the age of 1 year old. Sexual play in children, as well as masturbation, looks completely different from that of adults, of course. Indeed, children are motivated by curiosity, desire to discover their own body and others’, and simply by positive sensations. Therefore, they don’t carry the erotic connotation typical of adult sexual activity. As Sanderijn sharply highlighted during the lecture, this is one of the main misunderstandings when it comes to sexuality education: the people who oppose it generally project adult sexual behaviour and desires onto that of children; in reality, sexuality education is adapted to each stage of life, respecting the differences. Some examples of sexual play include watching and touching, playing doctor, kissing games, and copying sexual behaviour with dolls. They can be distinguished from other kinds of games by the children themselves, who describe these experiences as different from the other kinds of play they participate in. In fact, they report more physical feelings that they perceive right in their gut. For this reason, it is important for educators and caregivers to pay attention to such interactions, ensuring that all children involved feel comfortable, are willing participants, and that the activities remain appropriate for their age and context. Education on consent begins sooner than generally perceived, and it’s an educational responsibility to integrate sexuality education right from the early years of schooling, and to initiate conversations about it whenever we perceive that there’s a need to.
The Sensoa Flag System – A screenshot from the Sensoa Website
Assessing children’s comfort in sexual play, however, is not always straightforward. To support educators in this process, Sensoa developed the Flag System—an evidence-based tool that categorizes sexual behaviour into four levels, from okay to not okay at all (read more about the Sensoa Flag System). It also displays the most common scenarios, presenting appropriate responses for each one of them. It’s a guide for the assessment of sexual behaviour, which provides the user with four different flags as an outcome (green, yellow, red and black) to help the evaluation. The six criteria it is based on are the following: mutual consent, voluntary engagement, equality, level of development or functioning, context, and impact. Each one of these sections includes a list of specific guiding questions; it’s important to highlight how mutual consent and voluntary engagement occupy the first two elements to evaluate. Ultimately, the Sensoa flag system constitutes a valuable and innovative tool to help sexual behaviour assessment and highlights how consent is fundamental in relationships between children.
Sanderijn delivered a lecture at the University of Amsterdam, on March 4th, 2026
Furthermore, during her lecture at UvA, Sanderijn delved into the Dutch context regarding sexual behaviour trends, shedding light on a phenomenon endemic to Dutch society: the tendency for young people to progress through their sexual lives in gradual steps. According to Sex Under 25 Programme data (Rutgers, 2024), on average, among Dutch Youth, there is a two-year gap between the first kiss and the first penetrative intercourse.
In general, young people approach all sexual stages – including masturbation, French kissing, manual sex, oral sex, and vaginal intercourse – in a gradual and consecutive manner. From these data, we can infer that Dutch youth do not feel a rush to progress through these stages; instead, they feel free to explore their sexuality at a slower, more independent pace. This phenomenon is endemic to Dutch society and can be attributed to several factors.
Some explain this trend by linking it to the Comprehensive Sexuality Education (CSE) programs in Dutch schools, which emphasize consent and making responsible choices regarding one’s sexual life. Another key factor is a parenting style that often grants freedom to children and young couples from adolescence onwards – for instance, allowing them to have sleepovers from early on. Consequently, young people have the opportunity to engage in physical contact as they choose, which ensures they do not feel pressured or in a hurry to advance (van de Doef, 2018).
Despite this, data from Sex Under 25 (Rutgers, 2024) also show that sexual harassment and violence are increasing (as you can read about it in my fellow intern Lena’s blog), which may appear counterintuitive. One possible explanation is that the topic has received significant public attention in recent years, leading to greater awareness and, consequently, increased reporting of such experiences.
If CSE is widely implemented in the Netherlands, what might still be missing? According to Sanderijn, the challenge lies not only in understanding consent in theory, but in recognizing how it is expressed in practice—especially when it is not stated clearly or verbally. Consent is often communicated through subtle, implicit signals that require careful interpretation and receptivity. The challenge, therefore, lies in accurately understanding these cues, which is why sexuality education programs should place greater emphasis on developing this skill. To address this issue, multiple campaigns have been created in the last few years in the Netherlands. One of the most well-known is the campaign launched by Rutgers, Ben Je Okay? aimed at preventing sexual misconduct in bars, clubs and student associations. Its focus is indeed on identifying potential misconduct signals promptly.
Sanderijn delivered a lecture at the University of Amsterdam on March 4th, 2026
Another important element to consider when discussing the role of consent in sexuality education in the Netherlands is the Sex Offences Act, enacted in 2024, which represents a significant shift in Dutch legislation. The Act broadens the definition of sexual violence by establishing the absence of consent as a central criterion in determining offences such as rape. Unlike the previous legal framework, which required the presence of physical force or threats, the current law recognizes that sexual violence can occur even in their absence.
Under this law, sexual contact constitutes a criminal offence where it is clear—or where it reasonably should have been clear—that one of the parties did not consent. In this sense, the legislation places greater responsibility on individuals to ensure that consent is present. As such, it shifts the focus from physical violence to mutual consent, marking an important legal development and reflecting a broader cultural shift in how sexual autonomy and responsibility are understood.
In conclusion, the lecture by Sanderijn at UvA covered several points and topics, although for all of them, we can draw the importance of consent. From sexual play in childhood – individual and with others – to the development of sexual behaviour during teenage years, until the latest legislative developments, consent plays a crucial role, and its role needs to be assessed primarily – but not only – in sexuality education programs and within educational settings.
Furthermore, according to the Sex Under 25 research (Rutgers, 2024), young Dutch students are actively requesting more sexuality education in schools and more open dialogue on these topics in general. This highlights the responsibility of educational settings in initiating these conversations and driving social change.
Therefore, consent is not only a social matter, but also an educational and legislative one.
We presented CUE ‘s work after Sanderijn’s lecture
After her lecture, Sanderijn invited us to join her on stage and introduce CUE and our work to the students at UvA. It was a valuable opportunity to connect the themes discussed in the lecture with CUE’s practice, particularly in curating supportive programs, tools and events for individuals navigating the complex life transitions of emerging adulthood, and in the area of sexuality. We are very grateful for this opportunity to engage with the students, exchange perspectives, and share our the Consent Lab and Intimacy IQ Test with everyone.
References:
Rutgers. (2024). Sex under 25 2023: Sexual health of young people in the Netherlands. Utrecht: Rutgers.
Sensoa. (n.d.). Flag system: How to respond to transgressive sexual behaviour.
van der Doef, S., & Reinders, J. (2018). Stepwise sexual development of adolescents: the Dutch approach to sexuality education. Nature reviews. Urology, 15(3), 133–134. https://doi.org/10.1038/nrurol.2018.3
