I am repeating what I have already written on a different thread but based on all the research I have read even so called "safe co-sleeping" meaningfully increases the risk of SIDS:
bmjopen.bmj.com/content/3/5/e002299.full
"When neither parent smoked, and the baby was less than 3 months, breastfed and had no other risk factors, the AOR for bed sharing versus room sharing was 5.1 (2.3 to 11.4) and estimated absolute risk for these room sharing infants was very low (0.08 (0.05 to 0.14)/1000 live-births). This increased to 0.23 (0.11 to 0.43)/1000 when bed sharing. Smoking and alcohol use greatly increased bed sharing risk."
In other words, "safe" bed sharing increases SIDS risk by a factor of 3.
The study also refers to Netherlands where SIDS rates went down after an active campaign to discourage bed sharing.
Of course, it is up to the parents to make their own decisions but it is always useful to know all the facts. Even "safe" co-sleeping does not appear fully safe. It is possible to reduce the risk but it will not be as safe as having the baby in a separate Moses basket or cot in the room with parents.
FWIW - I have taken a risk based decision and moved my baby to a separate room when she was 12 weeks. I did consider co-sleeping when she was a newborn but decided not to go that route after looking at the stats.