These are just three examples of a number of controversies to be debated at events open to all during the British Science Festival in Aberdeen this week.
The biggest science festival in Europe is coming to Scotland for the first time.
There are almost 250 events taking place with internationally renowned scientists attending including Professor Brian Cox, who will discuss the quantum universe, and Richard Wiseman, who will explain why we dream and present the new technology that claims to be able to create your perfect dream.
Academics from five Scottish universities will explain the science of attraction, chemist and mixologist Noel Jackson will present a hands-on scientific guide to making the perfect cocktail and a team from Bubblestrings are aiming to break the world record for the biggest bubble.
The sperm warfare session will explain the devious tricks employed to win the race to fertilisation. Forsenic experts and a pathologist will test local crime writer Stuart MacBride’s scientific accuracy in a specially written short story.
And finally, kids are invited to learn how fireworks work, attend a magic show looking at the science behind superhero powers and explore the secret life of snot.
Historic Scotland is sponsoring a number of sessions showing how science is helping to understand and preserve the past. This includes the Scottish Ten project which aims to create accurate digital models of the five Scottish UNESCO designated World Heritage sites, and five international ones.
The Festival will also showcase how Scottish science is helping to solve global problems, in energy, water and food security.
One example is how technology from the whisky industry has been adapted into a new method of water purification.
The Festival is on from Tuesday 4 September until Sunday 9 September, promising ground-breaking science, controversial debates and lots of fun.