Says it would cause the testicles and surrounding tissue to grow through lydig cell stimulation. Same thing that happens during puberty. Take it for what it's worth.
Where in the 4 page study does it say that?
The following is not from the study and is only of opinion from the person who linked to the studies abstract.
"I do think that this is not sufficiently emphasized by anti-doping campaigns: athletes who dope with testosterone and anabolic steroids will cause their penises to become as small as their thumbs or little fingers, and unfortunately, if exogenous testosterone or anabolic steroids are taken for some time, the loss in size can be permanent. The effect of tongkat ali is the opposite. Because tongkat ali stimulates the body’s own testosterone production in the Leydig cells of the testicles, the testicles and surrounding tissue will grow in size. (During puberty, it's a spur in Leydig cell activity, which causes a boy's sexual organs to become the size of a man's. Furthermore, testosterone over-production endocrine disorders during adolescence cause oversized male genitalia.) "
Leydig Cell testosterone production is also not the cause of penile growth in puberty. If it was, testosterone alone would be enough to chemically increase the size of the penis, of which it cannot. Testicle size will increase from a higher Leydig cell activity, but not penile size.
I would do more reading into the studies themselves and not the opinions surrounding the studies if I were you.