Modifiers matching estrogen:

• natural,
• endogenous,
• steroidal,
• exogenous,
• synthetic,
• nonsteroidal,
• active,
• carcinogenic,

Simple categories matching steroidal:

• drug,
• estrogen,
• material,
• hormone,
• cream,
• medication,
• receptor,
• substance,
• androgen,
• progestin,
• agent,
• substrate,
• compound,