He frames the issue in terms of whether people see yoga poses as religious practices.
For many people, the main concern in a yoga class is whether they are breathing correctly or their legs are aligned. But for others, there are lingering doubts about whether they should be there at all, or whether they are betraying their religion...Opposition to yoga comes from many religious sources, most prominently Islamic and Christian clergy. Some Americans came up with a way of resolving some objections through clever rebranding.
Farida Hamza, a Muslim woman living in the US, had been doing yoga for two or three years when she decided she wanted to teach it.
"When I told my family and a few friends, they did not react positively," she recalls. "They were very confused as to why I wanted to do it - that it might be going against Islam."
Their suspicions about yoga are shared by many Muslims, Christians and Jews around the world and relate to yoga's history as an ancient spiritual practice with connections to Hinduism and Buddhism.
Last year, a yoga class was banned from a church hall in the UK. "Yoga is a Hindu spiritual exercise," said the priest, Father John Chandler. "Being a Catholic church we have to promote the gospel, and that's what we use our premises for." Anglican churches in the UK have taken similar decisions at one time or another. In the US, prominent pastors have called yoga "demonic".
One answer to the question of whether yoga really is a religious activity will soon be given by the Supreme Court in the country of its birth, India.
Last month, a pro-yoga group petitioned the court to make it a compulsory part of the school syllabus on health grounds - but state schools in India are avowedly secular. The court said it was uncomfortable with the idea, and will gather the views of minority groups in the coming weeks.
Children at nine primary schools in Encinitas, California, take part in classes twice a week based on a style of yoga called ashtanga yoga. After some parents complained - US schools, like Indian ones, are secular - the Sanskrit names for the postures were replaced with standard English names and some special child-friendly ones, such as "kangaroo" "surfer" and "washing machine". The lotus position has been rebranded "criss-cross apple sauce", the Surya namaskar has become the "opening sequence" and the organisers insist that it is all just a form of physical exercise.Islamic yoga objections are more worrisome as the proponents of yoga in Muslim lands try to "avoid a fatwa".
Some parents remained unconvinced though, and a Christian organisation, the National Center for Law & Policy (NCLP) took up their case. In September this year, the San Diego County Superior Court ruled that although yoga's roots are religious, the modified form of the practice is fine to teach in schools.
A founding member of the Iranian Yoga Federation spoke to the BBC. She did not wish to give her name.Kremer emphasizes the mystical nature of yoga for some Jewish practitioners.
We are always walking on eggshells as yoga instructors, afraid that the doors to the practice will be closed.
When I'm teaching yoga I always emphasise that it's not a religion. It's not Hindu or Buddhist. It's a philosophy and an approach. It's a practice that can make you feel better. It improves your concentration and gives you energy - although we always have to be very careful when we mention energy as this can be misinterpreted. We're working hard to avoid getting a fatwa.
But it's interesting - we actually had a mullah who was a yoga teacher and lots of families of senior clerics who attend classes too.
Estelle Eugene co-runs the Jewish Yoga Network and for 20 years has taught yoga to Jewish and non-Jewish people in London.Bottom line: Is yoga kosher?
"I've found with general Judaism here that it's difficult to find a spiritual side that I relate to," she says. "So the yoga helps me to do that. And it enhances my respect and understanding of Jewish practices that I hadn't fully understood previously."
She says she makes small adjustments to yoga where she feels there is a conflict with Judaism. She never attends or holds a class on the holy day, Saturday, and she prefers classes without the chanting of mantras.
Eugene recently ran a Day of Jewish Yoga, which explored ways of combining yoga with Judaism. One of the sessions combined yoga with practices to help participants reach kavanah, the meditative mind-set seen as an essential for Jewish prayer and rituals.
On her website, a testimonial from Rabbi David Rosen, the former chief rabbi of Ireland, says yoga offers "much blessing and enlightenment" and arguably helps "recapture Jewish wisdom and practice which may have been lost".
I practiced yoga for several years under the guidance of Bonnie West, a wonderful American teacher in Minneapolis. I increases my flexibility and balance through the poses and learned to settle my consciousness through its meditations. I derived great benefits from practicins yoga. And I never once felt any conflict between my yoga and my Judaism.
Yes, yoga is kosher for me. Your experiences may vary depending on who you are and where you are coming from, as the BBC article deftly suggests.