Churches are seeking a change to the law to expand safeguarding protections in faith organisations and sports clubs.
The current provisions around 'positions of trust' make it illegal for teachers, care workers and youth justice staff to engage in sexual activity with a 16- or 17-year-old under their supervision. However, they do not extend to adults in similar positions of authority within churches or sports teams.
In a report launched on Tuesday, the All-Party Parliamentary Group (APPG) on Safeguarding in Faith Settings warned that the current loopholes are leaving 16- to 17-year-olds exposed to greater risk of grooming and abuse, and making it possible for faith leaders or sports coaches to engage in sexual activity with them "with impunity".
The APPG wants to see the law changed so that the definition of 'positions of trust' is extended to any adult working with children while in a position of trust.
"There should be no difference in the protections afforded to young people in a school environment and those granted in other settings where they spend time alone with adults," the report reads.
"Adults who, in a position of trust, often hold considerable power and influence over them. Young people attending youth groups at their church, participating in a gymnastics team or having driving lessons experience this disparity and are more vulnerable because of it.
"From the evidence submitted to the inquiry from survivors, faith and religious organisations, the voluntary and public sector, there is a clear consensus that the definition of 'positions of trust' needs revising in order to allow better protection for young people in all settings."
The report warns that adults holding formal positions in faith organisations "are automatically seen as having authority, power and influence", which "can cause a power imbalance between those adults and the people within their congregation".
It said there was a "significant" opportunity for leaders in faith settings to abuse the power and trust placed in them, leaving people under their care feeling a sense of "powerlessness".
"Opportunities for abuse are common," the report says.
"Contact for faith leaders and others with children and young people can be direct, regular and intense creating significant opportunities for grooming and abuse.
"Such an environment can lead to young people (and their families) placing significant trust in their leaders and failing to question potential abusive behaviour and adherence to good safeguarding practices."
The APPG said that a number of organisations it had spoken to felt that the current legislation "lacks clarity", and that there could be wrong assumptions around the extent of the law.
"Many young people and parents assume that legislation prevents leaders and workers in faith settings from engaging in sexual activity with children under their care, however this is not the case," the report said.
Sarah Champion, MP for Rotherham and Chair of the APPG, said: "It makes no sense that young people should be protected from grooming and sexual abuse at school but not at their church or football club.
"Children attending youth groups at their church, participating in a gymnastics team or having driving lessons are vulnerable because the current law does not prevent the adults supervising them from engaging in sexual activity."
Justin Humphreys, CEO of the independent Christian safeguarding charity, Thirtyone:eight, which partnered in preparing the report, said: "The existing loophole in the law allows adults who clearly meet the criteria of being in a position of trust, such as a faith leaders or workers, to engage in sexual activity with 16 and 17 year olds in their care with impunity.
"This leaves young people at risk of grooming and sexual abuse at the hands of adults assigned power and trust."
The call is being supported by the Church of England, Catholic Church, Baptist, Methodist and United Reformed Churches.
The Baptist Union of Great Britain said: "We support the work currently underway to extend the positions of trust legislation to include those in leadership roles in religious organisations.
"Specifically, we see great value in extending the definitions to those in ministry roles, church leadership, regional and national structures, chaplaincy and a wide range of leaders who work with children and young people.
"We also believe the ability to automatically refer cases involving adults in a position of trust within the church to the police would assist in the handling of investigations, and therefore the safeguarding of children and young people."
In a written submission to the APPG, the Methodist Church said: "The extent of roles included in the legislation limits the potential impact and there is a perception that the concept of a 'position of trust' already extends beyond those currently specified in law."
Ms Champion MP said that with such broad support, there was no reason for the Government to resist the changes.
"The risk is particularly high in faith settings because adults holding positions in faith organisations are automatically seen as having authority, power and influence and the opportunity for abuse of that power is significant," she said.
"It is not appropriate for an adult who has responsibility for supervising a child to engage in sexual activity with them and the law must be changed to recognise this. This issue can be easily remedied by a simple change in the law."