I think in Tennis many women are using where as the men seem less likely to. I'm sure some do but the mens game seems more athletic especially with 5 sets and top guys are top guys for ages. Some of the women actually show up a bit fat even like Serena and Azarneka who I remember watching when she was 20 and had one of the best bodies ever. I'm sure there's a decent percentage that use but it's not like other sports where you have to use or you're not even in the mix.
Serena 100% on. Sam Stoser I think so. Maresmo? years ago was a massive user. I'm sure there are some that don't too.
Also Stoser being Aussie, lets face it as a fellow Aussie I can say they are the biggest fucking liars when it comes to PED use and are taught to lie and lie and lie and yet are the biggest users. Look at the swimmers

One thing i would say goes against some of them using is they are touring year round, especially the men. It would be very hard to be consistent with drugs the whole time, coming off one tournament, travelling to another over and over. Serena seemed to take long breaks (Failed drug tests most likely but not being made public). Even if they had a coach i'm sure it would be very hard to be consistent with using all the time when they are touring all the time.