Repeatedly, Roman sex cult is to do controversial experiments (8)
I believe the answer is:
vivisect
'to do controversial experiments' is the definition.
I can't judge whether this defines the answer.
'repeatedly roman sex cult' is the wordplay.
'repeatedly' says to double the letters.
'roman sex' becomes 'vi' ('sex' is Latin for 'six' or VI in Roman numerals. I am not sure about the 'roman' bit.).
'cult' becomes 'sect' (I've seen this before).
'vi' doubled is 'vivi'.
'vivi'+'sect'='VIVISECT'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for vivisect that I've seen before include "Operate on (a live animal)" , "Operate on living animal" .)